docum.txt

The GOLEM tokamak bibliography
The tokamak GOLEM team
April 11, 2024

Official GOLEM Articles
Abbasi et al.: Plasma diagnostics using fast cameras at the GOLEM tokamak

Abbasi-2023-FUSENGDES23

S. Abbasi et al. “Plasma diagnostics using fast cameras at the GOLEM tokamak”. In: Fusion Engineering and Design 193 (2023),
p. 113647. issn: 0920-3796. doi: https://doi.org/10.1016/j.fusengdes.2023.113647. url: https://www.sciencedirect.
com/science/article/pii/S0920379623002302.
Abstract: Tomographic inversion of radiation determines spatial distribution of tokamak plasma radiation sources using line integrated plasma projections data. For measurements of the projections, fast visible radiation matrix cameras became broadly applied
on tokamaks in recent past. These novel cameras opened new possibilities in high temperature plasma studies. The GOLEM tokamak of the Czech Technical University in Prague strives to implement up-to-date diagnostics with enhanced temporal and spatial
resolution. Therefore, a novel diagnostic system of two crossed monochrome cameras Photron FASTCAM MINI UX50 was integrated into the GOLEM diagnostics. The proposed contribution will detail their novel port mounts (vertical and horizontal) at the
GOLEM tokamak which have been designed so that additional optical measurements of the plasma core (e.g. plasma spectroscopy)
is possible. As the main purpose of this study, we shall focus in particular on the frame rate potential which is high enough to make
detection and observation of highly transient phenomena in the GOLEM plasmas possible. Progress in solving specific challenges
of the ill-conditioned tomographic inversion via the algorithm optimization and testing for the GOLEM tokamak will be presented
together with the first tomographic results.
Mácha et al.: Spontaneous formation of a transport barrier in helium plasma in a tokamak with circular configuration
Macha-2023-NuclFus
Petr Mácha et al. “Spontaneous formation of a transport barrier in helium plasma in a tokamak with circular configuration”. In:
Nuclear Fusion (Aug. 2023). doi: {10.1088/1741-4326/acf1af}.
Abstract: We report on the first experimental observation of a spontaneously formed transport barrier in the tokamak with a circular
configuration in helium plasmas. There was no external polarization of the plasma by electric field or other technique to form the
barrier as it is typically used in tokamaks with circular plasma. In general, the transport barriers play an important role in plasma
confinement especially in tokamaks with divertor configuration. In our experiments, we clearly observe distinct characteristics of
a transport barrier, including a steep gradient of the electron temperature and an enhanced radial electric field along with the
change in the plasma potential, floating potential, and electron temperature fluctuation. The electron temperature and the plasma
potential are obtained by a combination of the ball-pen and Langmuir probe measurements with high temporal resolution on a
shot-to-shot basis. This first experimental observation of the spontaneously formed transport barrier might bring new possibilities
to obtain a fusion-relevant study of the edge plasma parameters and transport in helium plasmas even on small tokamaks.
Sarancha et al.: Remote Plasma Physics Research and Teaching by Example of Turbulence Study at the UniversityScale Tokamak GOLEM
Sarancha-2023-FST
G. Sarancha et al. “Remote Plasma Physics Research and Teaching by Example of Turbulence Study at the University-Scale
Tokamak GOLEM”. In: Fusion Science and Technology 79.4 (2023), pp. 432–445. doi: 10.1080/15361055.2022.2148842. eprint:
https://doi.org/10.1080/15361055.2022.2148842. url: https://doi.org/10.1080/15361055.2022.2148842.
Abstract: AbstractThe university-scale tokamak GOLEM provides a unique opportunity to perform remote thermonuclear experiments [V. Svoboda, J. Fusion Energy, Vol. 38, Part 2, p. 253 (2019)]. Undergraduate plasma physics students from three
universities—Moscow Institute of Physics and Technology (National Research University), RUDN University, and National Research Nuclear University MEPhI—carried out joint remote experiments to train in tokamak operation and to study topics relevant
for mainstream fusion research such as plasma start-up, comparison of hydrogen versus helium plasma characteristics, electrostatic
and electromagnetic turbulence, long-range correlations, etc. New observations of the long-range correlations between low-frequency
(¡50 kHz) quasi-coherent electrostatic and magnetic oscillations identified as m = 2 mode with several techniques were done, as
well as of the broadband (¡250 kHz) magnetic oscillations resolved in frequency and wave vector in helium and hydrogen plasmas.
The presence of broadband electrostatic and broadband magnetic turbulence has also been established at the plasma edge.

1

Cerovsky et al.: Progress in HXR diagnostics at Golem and COMPASS tokamaks

Cerovsky-2022-JINST

J. Cerovsky et al. “Progress in HXR diagnostics at Golem and COMPASS tokamaks”. In: Journal of Instrumentation 17.01 (Jan.
2022), p. C01033. doi: 10.1088/1748-0221/17/01/c01033. url: https://doi.org/10.1088/1748-0221/17/01/c01033.
Abstract: Scintillation detectors are widely used for hard X-ray spectroscopy and allow us to investigate the dynamics of runaway
electrons in tokamaks. This diagnostic tool proved to be able to provide information about the energy or the number of runaway
electrons. Presently it has been used for runaway studies at the Golem and the COMPASS tokamaks. The set of scintillation detectors
used at both tokamaks was significantly extended and improved. Besides NaI(Tl) (2 x 2 inch) scintillation detectors, YAP(Ce) and
CeBr3 were employed. The data acquisition system was accordingly improved and the data from scintillation detectors is collected
with appropriate sampling rate (approx. 300 MHz) and sufficient bandwidth (approx. 100 MHz) to allow a pulse analysis. Up to
five detectors can currently simultaneously monitor hard X-ray radiation at the Golem. The same scintillation detectors were also
installed during the runaway electron campaign at the COMPASS tokamak. The aim of this contribution is to report progress in
diagnostics of HXR radiation induced by runaway electrons at the Golem and the COMPASS tokamaks. The data collected during
the 12th runaway electron campaign (2020) at COMPASS shows that count rates during typical low-density runaway electron
discharges are in a range of hundreds of kHz and detected photon energies go up to 10 MeV (measured outside the tokamak hall).
Acquired data from experimental campaigns from both machines will be discussed.
Kulkov et al.: Detection of runaway electrons at the COMPASS tokamak using a Timepix3-based semiconductor
detector
Kulkov-2022-JINST
S. Kulkov et al. “Detection of runaway electrons at the COMPASS tokamak using a Timepix3-based semiconductor detector”. In:
Journal of Instrumentation 17.02 (Feb. 2022), P02030. doi: 10.1088/1748- 0221/17/02/p02030. url: https://doi.org/10.
1088/1748-0221/17/02/p02030.
Abstract: Runaway electrons are considered dangerous for the integrity of tokamak vacuum vessels. To secure the success of the
future tokamak-based machines, reliable diagnostics and mitigation strategies are necessary. The COMPASS tokamak supported the
research of runaway electron physics via regular experimental campaigns. During the last two experimental campaigns dedicated to
runaway electrons, a semiconductor detector with a Timepix3 readout chip, Si sensor, and the SPIDR readout system was tested.
Time evolution signals, energy measurements, and sensor snapshots collected with the Timepix3-based detector are presented.
Sarancha et al.: Magnetic turbulence and long-range correlation studies in the Golem tokamak
Sarancha-2021-JPCS
G Sarancha et al. “Magnetic turbulence and long-range correlation studies in the Golem tokamak”. In: Journal of Physics: Conference Series 2055.1 (Oct. 2021), p. 012003. doi: 10.1088/1742-6596/2055/1/012003. url: https://doi.org/10.1088/17426596/2055/1/012003.
Abstract: The small university-scale tokamak Golem equipped with the electric and magnetic probes becomes a test bench for
studying the plasma turbulence and Zonal Flows, which are the essential processes affecting the plasma confinement. The broadband (fBB < 250 kHz) magnetic turbulence was detected for the first time using the Mirnov probes. The two-dimensional (frequency–wavelength) Fourier power spectra S(k, f ) of the magnetic turbulence indicate the turbulence poloidal propagation. The
long-range correlations (LRC) between the signals of magnetic and electric probes installed at different toroidal cross-sections were
detected in the low-frequency range (fLRC < 60 kHz), which is similar to the plasma potential LRC range observed in other devices.
Sarancha et al.: Hydrogen and helium discharges in the Golem tokamak

Sarancha-2021-VANT

G.A. Sarancha et al. “Hydrogen and helium discharges in the Golem tokamak”. In: Problems Of Atomic Science And Technology,
Ser. Thermonuclear Fusion 4 (2021), pp. 92–110. doi: 10.21517/0202-3822-2021-44-4-92-110. url: https://doi.org/10.
21517/0202-3822-2021-44-4-92-110.
Abstract: The helium plasma properties and confinement remain an important area of research in modern fusion devices. This work
is dedicated to the helium plasma initiation and control in a small-scale tokamak Golem compared to hydrogen plasma. Helium and
hydrogen plasmas are comprehensively compared and the optimum operational conditions for the start-up are found. Long-range
correlations between lowfrequency (¡50 kHz) electrostatic and magnetic oscillations are found, as well as broadband (< 250 kHz)
magnetic oscillations resolved in frequency and wave vector in helium plasma.
Siusko et al.: Breakdown phase in the Golem tokamak and its impact on plasma performance

Siusko-2021-UJP

Y. Siusko et al. “Breakdown phase in the Golem tokamak and its impact on plasma performance”. In: Ukrainian Journal of Physics
66.3 (2021), pp. 231–239. url: https://ujp.bitp.kiev.ua/index.php/ujp/article/view/2020180.
Abstract: The effect of the breakdown phase on subsequent plasma parameters was investigated remotely in Golem tokamak. The
dependence of breakdown voltage and the breakdown time versus the time delay between the trigger of the toroidal magnetic field
B t and the trigger of toroidal electric field E t for different groups of the pressure magnitudes is built. The performed ex- periments
have shown that for Golem tokamak the shorter is temporal delay - the better mean plasma parameters are obtained. In addition,
the breakdown phase was discussed more detailed. In the discussion the analysis of the avalanche phase of the breakdown was
made. The dominant mechanism of particle loses during avalanche phase, future steps, tasks were discussed and set.

Gryaznevich et al.: Contribution of joint experiments on small tokamaks in the framework of IAEA coordinated
research projects to mainstream fusion research
Gryaznevich-2020-PST
M. Gryaznevich et al. “Contribution of joint experiments on small tokamaks in the framework of IAEA coordinated research projects
to mainstream fusion research”. In: Plasma Science and Technology 22.5 (Mar. 2020), p. 055102. doi: 10.1088/2058-6272/ab6d4d.
url: https://doi.org/10.1088%2F2058-6272%2Fab6d4d.
Abstract: Joint experiments (JEs) on small tokamaks have been regularly performed between 2005 and 2015 under the framework of
the International Atomic Energy Agency (IAEA) coordinated research projects (CRPs). This paper describes the background and
the rationale for these experiments, how they were organized and executed, main areas of research covered during these experiments,
main results, contributions to mainstream fusion research, and discusses lessons learned and outcomes from these activities. We
underline several of the most important scientific outputs and also specific outputs in the education of young scientists and scientists
from developing countries and their importance.
Novotny et al.: Runaway electron diagnostics using silicon strip detector

Novotny-2020-JINST

L. Novotny et al. “Runaway electron diagnostics using silicon strip detector”. In: Journal of Instrumentation 15.07 (July 2020),
p. C07015. doi: 10.1088/1748-0221/15/07/c07015. url: https://doi.org/10.1088%2F1748-0221%2F15%2F07%2Fc07015.
Abstract: We present a proof-of-principle measurement of runaway electrons in a small tokamak using a silicon strip detector.
The detector was placed inside the diagnostic port of the tokamak vessel and detected the runaway electron signal directly.
The measured signal was compared to the signal provided by other tokamak diagnostics, especially the hard X-ray scintillation
detector, which detects secondary photons created by interaction of accelerated electrons with tokamak walls (indirect detection of
runaway electrons). The preliminary results show that when not saturated, direct detection with a segmented silicon strip detector
provides promising new diagnostic information including spatial and temporal distribution of the runaway electron beam, and the
measurement results are in good agreement with hard X-ray measurements with a scintillation detector.
Dhyani et al.: Study of Runaway Electrons in Golem Tokamak

Dhyani-2019-JINST

P. Dhyani et al. “Study of Runaway Electrons in Golem Tokamak”. In: Journal of Instrumentation 14.09 (Sept. 2019), pp. C09029–
C09029. doi: 10.1088/1748-0221/14/09/c09029. url: https://doi.org/10.1088%2F1748-0221%2F14%2F09%2Fc09029.
Abstract: High loop voltage and low-density plasma discharges at the Golem tokamak present favorable conditions for the study of
the runaway electrons (RE). A probe is being designed and developed for the spectral measurement of the RE energy inside the last
closed flux surface of Golem tokamak plasma. Design of the probe is based on simulation results of the FLUKA code that estimates
the energy absorbed by the scintillating crystals and filters of various densities. In the simulations, graphite, stainless steel and
molybdenum were tested to filter the supra-thermal electrons. Since having different light yield, YSO (Y2SiO5:Ce), NaI(Tl) and
plastic (EJ-200) scintillating crystals were chosen for the simulations.
Stockel et al.: Operational Domain in Hydrogen Plasmas on the Golem Tokamak

Stockel-2019-JOFE

J. Stockel et al. “Operational Domain in Hydrogen Plasmas on the Golem Tokamak”. In: Journal of Fusion Energy 38 (Mar. 2019),
pp. 253–261. issn: 1572-9591. doi: 10.1007/s10894-019-00215-7.
Abstract: A series of discharges in hydrogen were performed in two experimental sessions. The vessel was not conditioned before the
first session, while inductive heating of the vessel and cleaning glow discharge were applied before the second session. Experimental
results from both sessions are compared, and optimum operational conditions for the majority of key plasma parameters are
determined. It is found that plasma performance with a properly conditioned vessel is significantly better, as expected. In particular,
a noticeable increase of discharge duration, and of the electron temperature is observed.
Svihra et al.: Runaway electrons diagnostics using segmented semiconductor detectors
Svihra-2018-FUSENGDES
Peter Svihra et al. “Runaway electrons diagnostics using segmented semiconductor detectors”. In: Fusion Engineering and Design
146 (2019). SI:SOFT-30, pp. 316–319. issn: 0920-3796. doi: https : / / doi . org / 10 . 1016 / j . fusengdes . 2018 . 12 . 054. url:
https://www.sciencedirect.com/science/article/pii/S0920379618308196.
Abstract: A novel application of strip and pixel silicon radiation detectors for study and characterization of run-away electron
events in tokamaks is presented. Main goal was to monitor runaway electrons both directly and indirectly. The strip detector was
placed inside the tokamak vacuum chamber in order to monitor the run-away electrons directly. Whereas the pixel detector was
placed outside the tokamak chamber behind a pin hole for monitoring the run-away electrons indirectly via radiation produce by
interaction of the electrons with the plasma facing material. Results obtained using the silicon detectors are compared with already
existing diagnostic methods consisting of scintillation devices detecting X-rays and photo-neutrons, providing the same results in
the observable comparisons. Tests with the pixel detector proved that the pinhole camera is able to extract spatial information
of interaction point (a place where the runaway electrons hit on the facing material) and the strip detectors indicate presence of
additional signal from throughout the discharge. The performed experiments are innovative, illustrating possible development of
new and easy to use diagnostic method.

Grover et al.: Remote operation of the Golem tokamak for Fusion Education

Grover-2016-FUSENGDES

O. Grover et al. “Remote operation of the Golem tokamak for Fusion Education”. In: Fusion Engineering and Design 112 (2016),
pp. 1038–1044. issn: 0920-3796. doi: 10.1016/j.fusengdes.2016.05.009.
Abstract: Abstract Practically oriented education in the field of thermonuclear fusion is highly requested. However, the high
complexity of appropriate experiments makes it difficult to develop and maintain laboratories where students can take part in
hands-on experiments in this field of study. One possible solution is to establish centres with specific high temperature plasma
experiments where students can visit such a laboratory and perform their experiments in-situ. With the advancements of {IT}
technologies it naturally follows to make a step forward and connect these with necessary plasma physics technologies and thus
allow to access even sophisticated experiments remotely. Tokamak Golem is a small, modest device with its infrastructure linked to
web technologies allowing students to set-up necessary discharge parameters, submit them into a queue and within minutes obtain
the results in the form of a discharge homepage.
Svoboda et al.: Remote operation of the Golem tokamak with hydrogen and helium plasmas

Svoboda-2016-JPCS

V. Svoboda et al. “Remote operation of the Golem tokamak with hydrogen and helium plasmas”. In: Journal of Physics: Conference
Series 768.1 (2016). doi: 10.1088/1742-6596/768/1/012002. url: https://www.scopus.com/inward/record.uri?eid=2-s2.084996848706&doi=10.1088%2f1742-6596%2f768%2f1%2f012002&partnerID=40&md5=e2758016f6bdd51be8c02e6f972a374e.
Abstract: The Golem tokamak was operated remotely via Internet connection during the 6th International Workshop and Summer
School on Plasma Physics. Performances of hydrogen and helium discharges are compared in this paper. It is found, at similar
vacuum conditions, that helium discharges are shorter but the breakdown of the working gas can be quite easily achieved at
almost the same loop voltage. The plasma current in helium discharges is slightly lower than in the case of hydrogen. Turbulent
fluctuations of the floating potential measured by means of an array of Langmuir probes reveal a noticeably different character in
the two discharges. c Published under licence by IOP Publishing Ltd.
Gryaznevich et al.: Contribution to fusion research from IAEA coordinated research projects and joint experiments
Gryaznevich-2015-NuclFus
M. Gryaznevich et al. “Contribution to fusion research from IAEA coordinated research projects and joint experiments”. In: Nuclear
Fusion 55.10 (2015), p. 104019. doi: 10.1088/0029-5515/55/10/104019.
Abstract: The paper presents objectives and activities of IAEA Coordinated Research Projects ‘Conceptual development of steadystate compact fusion neutron sources’ and ‘Utilisation of a network of small magnetic confinement fusion devices for mainstream
fusion research’. The background and main projects of the CRP on FNS are described in detail, as this is a new activity at IAEA.
Recent activities of the second CRP, which continues activities of previous CRPs, are overviewed.
Markovic et al.: Development of 3D ferromagnetic model of tokamak core with strong toroidal asymmetry
Markovic-2015-FUSENGDES
T. Markovic et al. “Development of 3D ferromagnetic model of tokamak core with strong toroidal asymmetry”. In: Fusion Engineering and Design 96-97 (2015), pp. 302–305. issn: 0920-3796. doi: 10 . 1016 / j . fusengdes . 2015 . 03 . 041. url: http :
//www.sciencedirect.com/science/article/pii/S0920379615002100.
Abstract: Abstract Fully 3D model of strongly asymmetric tokamak core, based on boundary integral method approach (i.e.
characterization of ferromagnet by its surface) is presented. The model is benchmarked on measurements on tokamak Golem, as
well as compared to 2D axisymmetric core equivalent for this tokamak, presented in previous work. Linearized model well describes
quantitative characteristics of {BR} field, generated by poloidal field coils located close to core central column, and distorted by
ferromagnet. A discrepancy is seen between linearized form of model for {BR} field generated by coils under the transformer limbs
and the measurements. Future work will thus include implementation of the non-linearity effects in order to further investigate this
issue.
Svoboda et al.: Remote operation of the vertical plasma stabilization @ the Golem tokamak for the plasma physics
education
Svoboda-2015-FUSENGDES
V. Svoboda et al. “Remote operation of the vertical plasma stabilization @ the Golem tokamak for the plasma physics education”.
In: Fusion Engineering and Design 96-97 (2015), pp. 974–979. issn: 0920-3796. doi: 10.1016/j.fusengdes.2015.06.044. url:
http://www.sciencedirect.com/science/article/pii/S0920379615300740.
Abstract: Abstract The Golem tokamak at the Czech Technical University has been established as an educational tokamak device
for domestic and foreign students. Remote participation in the scope of several laboratory practices, plasma physics schools and
workshops has been successfully performed from abroad. A new enhancement allowing understandable remote control of vertical
plasma position in two modes (i) predefined and (ii) feedback control is presented. It allows to drive the current in the stabilization
coils in any time-dependent scenario, which can include as a parameter the actual plasma position measured by magnetic diagnostics.
Arbitrary movement of the plasma column in a vertical direction, stabilization of the plasma column in the center of the tokamak
vessel as well as prolongation/shortening of plasma life according to the remotely defined request are demonstrated.

Gryaznevich et al.: Progress in application of high temperature superconductor in tokamak magnets
Gryaznevich-2013-FUSENGDES.pdf
M. Gryaznevich et al. “Progress in application of high temperature superconductor in tokamak magnets”. In: Fusion Engineering
and Design 88.9-10 (2013), pp. 1593 –1596. issn: 0920-3796. doi: 10 . 1016 / j . fusengdes . 2013 . 01 . 101. url: http : / / www .
sciencedirect.com/science/article/pii/S0920379613001117.
Abstract: It has long been known that high temperature superconductors (HTS) could have an important role to play in the future
of tokamak fusion research. Here we report on first results of the use of HTS in a tokamak magnet and on the progress in design
and construction of the first fully-HTS tokamak.
Markovic et al.: Evaluation of applicability of 2D iron core model for two-limb configuration of Golem tokamak
Markovic-2013-FUSENGDES
T. Markovic et al. “Evaluation of applicability of 2D iron core model for two-limb configuration of Golem tokamak”. In: Fusion
Engineering and Design 88.6-8 (2013), pp. 835 –838. issn: 0920-3796. doi: 10.1016/j.fusengdes.2013.02.142. url: http:
//www.sciencedirect.com/science/article/pii/S0920379613002573.
Abstract: This paper presents evaluation of applicability of 2D iron core model for highly non-axisymmetric two limb configuration of
Golem tokamak (former CASTOR). Presented results explain the long-term discrepancy between measured magnitudes of external
poloidal field and those calculated by air-core approach on this tokamak. The model has been applied to two poloidal planes at
different toroidal angles in the vacuum vessel region and has shown that close to central column of the transformer, it is possible to
correct for 3D effects by variation of chosen dimensions of axisymmetric iron core model. Satisfactory agreement of the 2D model
results with the measured distribution of {BR} field component was achieved.
Odstrcil et al.: Low cost alternative of high speed visible light camera for tokamak experiments

Odstrcil-2012-RSI

T. Odstrcil et al. “Low cost alternative of high speed visible light camera for tokamak experiments”. In: Review of Scientific
Instruments 83.10, 10E505 (2012). doi: 10.1063/1.4731003. url: http://scitation.aip.org/content/aip/journal/rsi/83/
10/10.1063/1.4731003.
Abstract: We present design, analysis, and performance evaluation of a new, low cost and high speed visible-light camera diagnostic
system for tokamak experiments. The system is based on the camera Casio EX-F1, with the overall price of approximately a
thousand USD. The achieved temporal resolution is up to 40 kHz. This new diagnostic was successfully implemented and tested at
the university tokamak GOLEM (R = 0.4 m, a = 0.085 m, BT ¡ 0.5 T, Ip ¡ 4 kA). One possible application of this new diagnostic
at GOLEM is discussed in detail. This application is tomographic reconstruction for estimation of plasma position and emissivity.
Svoboda et al.: Multi-mode Remote Participation on the Golem Tokamak

Svoboda-2011-FUSENGDES

V. Svoboda et al. “Multi-mode Remote Participation on the Golem Tokamak”. In: Fusion Engineering and Design 86.6-8 (2011),
pp. 1310–1314. issn: 0920-3796. doi: {10.1016/j.fusengdes.2011.02.069}.
Abstract: The Golem tokamak (formerly CASTOR) at Czech Technical University is demonstrated as an educational tokamak
device for domestic and foreign students. Remote participation of several foreign universities (in Hungary, Belgium, Poland and
Costa Rica) has been successfully performed. A unique feature of the Golem device is functionality which enables complete remote
participation and control, solely through Internet access. Basic remote control is possible either in online mode via WWW/SSH
interface or offline mode using batch processing code. Discharge parameters are set in each case to configure the tokamak for a
plasma discharge. Using the X11 protocol it is possible to control in an advanced mode many technological aspects of the tokamak
operation, including: i) vacuum pump initialization, ii) chamber baking, iii) charging of power supplies, iv) plasma discharge
scenario, v) data acquisition system.

Conference proceedings
Cerovsky et al.: Runaway electron studies via HXR spectroscopy at Golem, COMPASS and TCV
CerovskyECPD23
J. Cerovsky et al. “Runaway electron studies via HXR spectroscopy at Golem, COMPASS and TCV”. In: European Conference on
Plasma Diagnostics. Rethymno, Apr. 2023. url: http://golem.fjfi.cvut.cz/wiki/Presentations/Conferences/ECPD/5th_
Rethymno_2023/poster.pdf.
Abstract: The research on runaway electrons in tokamaks continues to be important for safe and reliable operation of large fusion
devices due to the potential risk of impact of so called runaway electron beams on plasma facing components which could cause
a serious damage and lead to putting the machine out of operation. In order to investigate the properties of runaway electrons
and provide useful information about their behavior under different experimental conditions (e.g. efficiency of various mitigation
techniques or exploration of runaway electrons free regimes) many dedicated diagnostics has been utilized. One way of inferring
features of runaway electrons is a measurement of their bremsstrahlung radiation which is generated by collisions with plasma ions
or by their impact on the first wall when runaway electrons are deconfined and lost. Recently, diagnostic capabilities at GOLEM [1]
were upgraded by installation of two scintillation detectors with CeBr3 crystals (1” x 1”), which were also successfully tested during

the dedicated runaway electron campaigns at the COMPASS tokamak [2]. Moreover, both scintillation detectors were also installed
at the TCV tokamak to extend for the first time the hard x-ray radiation diagnostics and provide an estimates of the maximal
energy of runaway electrons. The aim of this contribution is to describe the diagnostic used and experimental conditions of the
different devices. Additionally, illustrative examples of experiments from these three different devices are presented and acquired
data by the diagnostic system for HXR spectroscopy is discussed and put into the context. The comparison with other relevant
diagnostics is shown. At the GOLEM tokamak the spectroscopy system was used to observe the influence of the initial pressure of
the working gas and maximal energy of HXR photons was estimated about 300 keV. On the other hand at the COMPASS tokamak
[3], the data recorded in experiments focused on characterizing runaway electron beams properties and the efficiency of various
mitigation techniques (e.g. graphite pellet injection). At TCV [4], the installed set of scintillation detectors proved to be useful as
a source of complementary information to standard radiation diagnostics and helped to characterized generated runaway electrons
beams. This contribution also briefly shows a progress in modeling the radiation transport using FLUKA [5], carried out in order
to better interpret the obtained data.
Chlum et al.: Tokamak GOLEM for fusion education - chapter 14

ChlumECPP23

J. Chlum et al. “Tokamak GOLEM for fusion education - chapter 14”. In: vol. July. Europhysics conference abstracts. 2023.
Ivanov et al.: Runaway electrons measurements by ECE on the GOLEM tokamak

IvanovECPP23

V. Ivanov et al. “Runaway electrons measurements by ECE on the GOLEM tokamak”. In: vol. July. Europhysics conference
abstracts. 2023.
Macha et al.: Self-induced transport barrier in the helium plasma on the tokamak Golem

MachaEPS22-a

P. Macha et al. “Self-induced transport barrier in the helium plasma on the tokamak Golem”. In: vol. July. Europhysics conference
abstracts. 2022. url: https://indico.fusenet.eu/event/28/contributions/64/attachments/78/1153/EPS_2022_article.
pdf.
Abstract: Transport barriers and transmissions into different regimes of plasma confinement are currently very discussed topics.
The lattes research showed a connection between transport barriers and E x B shear flows, which are able to suppress turbulent
structures by tearing them apart. This process leads to better particle and also temperature confinement. Therefore, there is a
significant effort for transport barrier studies. Usually, transport barriers are induced by an external electric field, which is used for
plasma biasing. This method is useful, however, spontaneously formed transport barriers can provide more information about the
processes taking place in a tokamak plasma. In this paper, the self-induced transport barrier in the helium plasma on the tokamak
GOLEM is observed and analyzed.
Macha et al.: Tokamak Golem for fusion education - chapter 13

MachaEPS22-b

P. Macha et al. “Tokamak Golem for fusion education - chapter 13”. In: vol. July. Europhysics conference abstracts. 2022. url:
https://indico.fusenet.eu/event/28/contributions/164/attachments/178/1152/EPS_2022_golem_article.pdf.
Abstract: The contribution is devoted to the description of several students projects, related mainly to edge plasma diagnostics,
investigation of selected issues of tokamak physics and plasma performance on the GOLEM tokamak, particularly: i) Plasma stabilization, ii) A research on runaway electrons (RE) physics, iii) Plasma edge studies with electrostatic probes and iv) Tomography.
Kulkov et al.: Runaway electron study at the COMPASS tokamak using the Timepix3-based silicon pixel detector
with SPIDR 10 GBps readout
KulkovEPS21
S. Kulkov et al. “Runaway electron study at the COMPASS tokamak using the Timepix3-based silicon pixel detector with SPIDR
10 GBps readout”. In: vol. July. Europhysics conference abstracts. 2021, P3.1006. isbn: 979-10-96389-13-1. url: http://ocs.
ciemat.es/EPS2021PAP/pdf/P3.1006.pdf.
Abstract: Runaway electrons (RE) that appear in tokamak plasmas are considered dangerous for the integrity of the future tokamakbased fusion reactors due to a large amount of energy they carry. Therefore, it is necessary to understand properties of such electrons
in order to secure the success of future machines, e.g., ITER, which is one of the main topics of research at the COMPASS tokamak.
Semiconductor detectors, which are widely applied in high-energy physics, may be a suitable addition to plasma diagnostics as they
are not affected by magnetic fields and are well-equipped for soft X-ray spectra measurements. A hybrid pixel detection system
based on the Timepix3 readout chip with a 200 um thick silicon sensor (in the further text - Timepix3) is a perfect example of such
instrumentation.The Timepix3 sensor consists of 256 x 256 pixels with a pixel size of 55 x 55 um2 and, therefore, provides a high
spatial resolution. Combined with the SPIDR readout system, Timepix3 is capable of simultaneous recording of Time-of-Arrival
(ToA) and Time-over-Threshold (ToT) signals as well as pixel coordinates where the detection occurs with temporal resolution of
1.5625 ns. Additionally, from the number of pixels where a hit was detected, Timepix3 is able to determine either a photon, an
electron or a heavier particle was detected. This work presents results acquired with the Timepix3 during the 11th RE-dedicated
campaign conducted in 47th EPS Conference on Plasma Physics P3.1006 January, 2020 at the COMPASS tokamak.

Macha et al.: Tokamak Golem for fusion education - chapter 12

Macha-2021-ECPP

P. Macha et al. “Tokamak Golem for fusion education - chapter 12”. In: vol. July. Europhysics conference abstracts. 2021, P4.1028.
isbn: 979-10-96389-13-1. url: http://ocs.ciemat.es/EPS2021PAP/pdf/P4.1028.pdf.
Abstract: The GOLEM tokamak is the oldest tokamak in the world. Currently, it serves mainly as an education device for students
of tokamak physics. Remote control of the machine enables conducting experiments from all over the world. This contribution
summarizes its main research topics of the last year.
Malec et al.: Correlations in signals generated by runaway electrons in the GOLEM tokamak measured using the
Timepix3 detection modules
MalecIEEE21
S. Malec, V. Linhart, and V. Svoboda. “Correlations in signals generated by runaway electrons in the GOLEM tokamak measured
using the Timepix3 detection modules”. In: 2021 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC).
2021, pp. 1–6. doi: 10.1109/NSS/MIC44867.2021.9875920.
Abstract: An application study of modern pixel semiconductor detectors for characterization of runaway electron events in a
tokamak is presented. This study is based on comparative techniques utilizing spectroscopy and timing measurements of X-rays
produced by the runaway electrons. The measurements were performed on the tokamak Golem using three Advapix detection
modules. The first two modules were based on a Timepix3 R/O chip with a 1 mm thick silicon sensor. The last module was based
also on the Timepix3 R/O chip but with a 2 mm thick CdTe sensor. The modules were placed at different positions around the
tokamak chamber and were triggered by a common trigger signal. We have observed that energy spectra measured by the two
identical modules in the same place are identical. The spectra measured in different places show variations which can be used for
runaway electron characterization. The time evolution of the signals from the detection modules are well correlated. Comparison of
the time evolutions measured by the same two detection modules can be used for estimation of places where the runaway electrons
interact with the tokamak matter.
Dhyani et al.: Design and development of probe for the measurements of runaway electrons inside the Golem
tokamak plasma edge
DhyaniEPS19
P. Dhyani et al. “Design and development of probe for the measurements of runaway electrons inside the Golem tokamak plasma
edge”. In: vol. July. Europhysics conference abstracts. 2019, P1.1016. isbn: 979-10-96389-11-7. url: http://ocs.ciemat.es/
EPS2019PAP/pdf/P1.1016.pdf.
Abstract: FLUKA simulation results show that NaI(Tl) is a good candidate for the spectral measurement of the RE beam energy,
since the amount of energy deposited by monoenergetic beam in the crystals is different as shown in figure 4. Further simulations will
be carried out using GEANT4 and FLUKA codes, to interpret the signals obtained during the experiments. In GOLEM tokamak
experiments, we measure HXR outside the machine that has S.S. (density 8.0 g/cm3) vacuum vessel of 0.2mm surrounded by
a copper (density 8.96 g/cm3) donut shaped shield of thickness 10mm. Reported simulation results indicate that 2.5mm thin
graphite (density 2.1 g/cm3) shield was able to absorb 1MeV beam effectively, indicating that the RE beam in the GOLEM
tokamak has energy much higher than 1MeV, in general.
Grover et al.: Online experimentation at the Golem tokamak

GroverIEEE19-b

O. Grover, V. Svoboda, and J. Stockel. “Online experimentation at the Golem tokamak”. In: 2019 5th Experiment International
Conference (exp.at’19). June 2019, pp. 220–225. doi: 10.1109/EXPAT.2019.8876482. url: https://ieeexplore.ieee.org/
document/8876482.
Abstract: The Golem tokamak offers students and other interested parties the opportunity to gain ”hands-on” experience through
online experimentation in the field of plasma physics and controlled thermonuclear fusion in tokamaks. A typical online experiment
scenario is outlined. The new web application facilitating safe, easy and efficient online experimentation, including a live, realtime view of the experiment is described in detail. Simple access to the open and extensive database of experimental results is
demonstrated. Finally, the wide range of possible experimental topics from past -and applicable to future-online experimentation
sessions is reported.
Kulkov et al.: Tokamak Golem for fusion education - chapter 10

MachaEPS19

S. Kulkov et al. “Tokamak Golem for fusion education - chapter 10”. In: vol. July. Europhysics conference abstracts. 2019, P1.1068.
isbn: 979-10-96389-11-7. url: http://ocs.ciemat.es/EPS2019PAP/pdf/P1.1068.pdf.
Abstract: The GOLEM tokamak is the oldest tokamak in the world. Currently, it is located at the FNSPE CTU in Prague and it
serves mainly as an education device for students of tokamak physics. Remote control of the machine enables conducting experiments
from all over the world using an internet connection. This contribution summarizes main research topics of study of the last year.
O. Grover and V. Svoboda and J. Stockel: Remote demonstration of the Golem tokamak

GroverIEEE19-a

O. Grover and V. Svoboda and J. Stockel. “Remote demonstration of the Golem tokamak”. In: 2019 5th Experiment International
Conference (exp.at’19). June 2019, pp. 239–240. doi: 10.1109/EXPAT.2019.8876584. url: https://ieeexplore.ieee.org/
document/8876584.

Abstract: The Golem tokamak serves as an educational device in the field of tokamak physics, technology, diagnostics and operation
in the scope of the wider field of thermonuclear fusion. The typical scenario of a remote demonstration of the Golem tokamak is
described. The new remote control and live status web interface in its mobile-ready form is presented.
Istokskaia et al.: Tokamak Golem for fusion education - Chapter 9

IstokskaiaEPS18

V. Istokskaia et al. “Tokamak Golem for fusion education - Chapter 9”. In: vol. July. 2018, pp. 261–264. url: http://golem.
fjfi.cvut.cz/wiki/Presentations/Conferences/EPS/45th_Prague_2018/paper.pdf.
Abstract: The GOLEM tokamak, located at the FNSPE CTU in Prague, is the oldest tokamak in the world still operational. Its
main mission is education and training of future fusion specialists in the Czech Republic. This contribution covers various student
projects of the last year.
Linhart et al.: First Measurement of X-rays Generated by Runaway Electrons in Tokamaks Using a Timepix3
Device with 1 mm thick Silicon Sensor
LinhartIEEE18
V. Linhart et al. “First Measurement of X-rays Generated by Runaway Electrons in Tokamaks Using a Timepix3 Device with 1
mm thick Silicon Sensor”. In: 2018 IEEE Nuclear Science Symposium and Medical Imaging Conference Proceedings (NSS/MIC).
Nov. 2018, pp. 1–9. doi: 10.1109/NSSMIC.2018.8824534.
Abstract: An application study of modern pixel semiconductor detectors for characterization of runaway electron events in tokamaks
is presented. Characterization techniques utilizing both spectroscopic measurements and monitoring of the intensity of secondary Xrays produced by the runaway electrons were used. Energy spectra of X-rays and time evolutions of their intensity on two tokamaks
(Golem and Compass) were measured under different conditions and compared with results of standard runaway diagnostics. The
energy spectra measured on both tokamaks have similar exponential shapes but with a significant variation in numbers of events
per shot. The time evolutions of the X-ray intensity during several discharges on the tokamak Golem were measured using both
the Timepix3 device and scintillation detectors (NaI:Tl and YAP:Ce). On a microsecond time scales, the signal time evolution
measured by the TimePix3 device shows patterns in a form of unexpected or periodic-like increases of the intensity. We have also
observed significant differences in number of events of the detected X-rays generated by the runaway electrons flying frontward and
backward with respect to a limiter of the tokamak Golem. This fact declares that the runaway electrons have relativistic velocities.
The experiments on the tokamak Compass provide similar results. Measurements in the immediate vicinity of tokamak Compass
were impossible to perform because of a rapid change of the tokamak magnetic field. Measurements performed in the distance of
at least 0.5 m from a diagnostic port of the tokamak Compass gave millions of correctly measured events per shot and an unknown
number of events affected by pileups. The correctly measured events were used for construction of energy spectra and the time
evolutions of the X-ray intensity.
Duban et al.: Tokamak Golem for fusion education - chapter 7

EPSLeuven2016

R. Duban et al. “Tokamak Golem for fusion education - chapter 7”. In: Europhysics Conference Abstracts. 43th EPS Conference on
Plasma Physics. Vol. 40A. europhysics conference abstracts. 2016. isbn: 2-914771-99-1. url: http://ocs.ciemat.es/EPS2016PAP/
pdf/P5.009.pdf.
Abstract: As the oldest operational tokamak in the world, tokamak GOLEM at FNSPE CTU in Prague, Czech Republic serves
primarily to educate students of the faculty in tokamak physics and related fields. This contribution covers various student projects
of the last year.
Svoboda et al.: Tokamak Golem for fusion education - chapter 6

Svoboda15:235954

V. Svoboda et al. “Tokamak Golem for fusion education - chapter 6”. In: 42nd European Physical Society Conference on Plasma
Physics. 2015. isbn: 2-914771-98-3. url: http://ocs.ciemat.es/EPS2015PAP/pdf/P2.164.pdf.
Abstract: GOLEM is the oldest operational tokamak in the world. It serves as an educational device at the Facuty of Nuclear
Sciences and Physical Engineering at CTU in Prague. Several improvements of its diagnostic technology made during the last year
as well as new experimental results are presented in this article.
Ficker et al.: Tokamak Golem for fusion education - chapter 5

EPSBerlin2014

O. Ficker et al. “Tokamak Golem for fusion education - chapter 5”. In: Europhysics Conference Abstracts. 41th EPS Conference on
Plasma Physics. Vol. 38F. 2014. isbn: 2-914771-90-8. url: http://ocs.ciemat.es/EPS2014PAP/pdf/P4.141.pdf.
Abstract: Tokamak Golem is one of the oldest tokamaks in the world, currently located at the Faculty of Nuclear Sciences and
Physical Engineering, CTU in Prague. It serves as an educational device and all experiments and development are done by students
themselves under professional supervision. The contribution covers the major improvements made over the last year.
Hernandez-Arriaga et al.: Tokamak Golem for fusion education - chapter 4

EPSHelsinky2013

D. Hernandez-Arriaga et al. “Tokamak Golem for fusion education - chapter 4”. In: Europhysics Conference Abstracts. 40th EPS
Conference on Plasma Physics. Vol. 2013. isbn: 978-1-63266-310-8. url: http://ocs.ciemat.es/EPS2013PAP/pdf/P2.410.pdf.

Abstract: Tokamak GOLEM is a small tokamak operating at the Faculty of Nuclear Sciences and Physical Engineering at the
Czech Technical University in Prague. It has been serving for four years as an educational device for training students in fusion
research. One of its essential features is the possibility of fully remote operation so it suits to international experiments with broad
participation.This contribution concludes the main headlight topics of the last year.
Ball et al.: First results from tests of high temperature superconductor magnets on tokamak
EPSStockholm2012HTS
S. Ball et al. “First results from tests of high temperature superconductor magnets on tokamak”. In: Europhysics Conference
Abstracts. 39th EPS Conference on Plasma Physics. Vol. 36F. 2012. url: http://ocs.ciemat.es/epsicpp2012pap/pdf/P2.052.
pdf.
Abstract: The HTS coils have been routinely and successfully used at the GOLEM tokamak both for plasma generation and
stabilization. Provided the LN cooling is sufcient and sustained, the HTS coils are reliable and can greatly reduce the necessary
capacitor bank charging voltage,thus lowering the energy demands for plasma position control. The coil currents in fast ramp-up
pulse operation exceeded those in the tape specication by almost 50 %.
Svoboda et al.: Recent results from Golem tokamak. ’Indeed, you can teach an old dog some new tricks.
EPSStockholm2012
V. Svoboda et al. “Recent results from Golem tokamak. ’Indeed, you can teach an old dog some new tricks.” In: Europhysics
Conference Abstracts. 39th EPS Conference on Plasma Physics. Vol. 36F. 2012. url: http://ocs.ciemat.es/epsicpp2012pap/
pdf/P2.059.pdf.
Abstract: Hall sensors in a tokamak environment are being prepared on GOLEM. These sensors are one of the candidate solutions
for measurement of stationary magnetic fields in fusion reactors. Energy distribution of HXR photons was measured at several
discharge conditions on GOLEM using NaI(Ta) scintillator detector. Measured HXR photons spectrum ranges up to 1.5 MeV and
peaks typically at 300 keV. We assume the measured energy spectrum of HXR photons correspond to the energy distribution
of runaway electrons. Finally, the spatial and temporal characteristics of electrostatic turbulence in GOLEM edge plasmas were
studied using the radial array of 16 Langmuir probes. Comparison of turbulence properties between standard hydrogen and helium
discharges was done.
Bromova et al.: The Golem Tokamak for Fusion Education

EPSStrasbourg2011

E. Bromova et al. “The Golem Tokamak for Fusion Education”. In: Europhysics Conference Abstracts. 38th EPS Conference on
Plasma Physics. Vol. 35G. 2011. isbn: 2-914771-68-1. url: http://ocs.ciemat.es/EPS2011PAP/pdf/P1.021.pdf.
Abstract: The Golem tokamak, (formerly CASTOR), became an educational device for domestic as well as for foreign students via
remote participation/handling. It operates routinely for nearly two years at modest range of parameters and with a limited set
of diagnostics. Wide range of tasks with varying levels of complexity covering tokamak physics, technology and operation can be
studied by the future fusion specialists. Currently the diagnostics enrichment is strategic for the education usability of the device.
Students participate in large extent on additional standard diagnostics methods development, including density measurement via
microwave interferometry, plasma position (including tomography) studies using a set of Mirnov coils, two fast cameras and two
linear arrays of bolometers. Moreover stabilization of the plasma position with an equilibrium magnetic field generated in the
vertical magnetic field coils and plasma spectroscopy issues are under consideration.
Svoboda et al.: Tokamak Golem Remotely for Worldwide Fusion Education

Svoboda11:186333

V. Svoboda and J. Stöckel. “Tokamak Golem Remotely for Worldwide Fusion Education”. In: Proceedings: SEFI - PTEE 2011.
Hochschule Mannheim - University Of Applied Sciences, 2011. isbn: 978-3-931569-18-1. url: http://sefi11.hs-mannheim.de/
index.php?option=com_content\&view=article\&id=27\&Itemid=27.
Abstract: The GOLEM tokamak is a university-type experimental facility dedicated primarily for practical training of students
who are familiar with basics of tokamak operation, data processing and evaluation of selected plasma parameters. Wide range
of measurement tasks allows for preparation of different level student measurement programs. The Czech Technical University
established in 2006 a new education curriculum ”The physics and Technology of Thermonuclear Fusion”. The GOLEM tokamak
carries out its education mission in the frame of the fusion related practicum, bachelor and diploma thesis, and summer training
schools. Furthermore, a number of excursions are regularly organized for various Czech high schools. As a result, some motivated
high school students can participate in tokamak operation and solve selected elementary problems.
Svoboda et al.: Former Tokamak CASTOR becomes remotely controllable Golem at the Czech Technical University
in Prague
EPSDublin2010
V. Svoboda et al. “Former Tokamak CASTOR becomes remotely controllable Golem at the Czech Technical University in Prague
”. In: Europhysics Conference Abstracts. 37th EPS Conference on Plasma Physics. Vol. 34A. 2010. isbn: 2-914771-62-2. url:
http://ocs.ciemat.es/EPS2010PAP/pdf/P2.111.pdf.

Abstract: The CASTOR tokamak, which has been operated for 30 years at the IPP Prague was moved to the Czech Technical University in Prague and became an educational device for domestic as well as for foreign students, via remote participation/handling.
The reinstalled tokamak (R = 0.4 m, a = 0.085 m), now baptized as GOLEM, operates currently at modest range of parameters,
Bt ¡ 0.8 T, Ip ¡ 8 kA, discharge duration approx 13 ms, and with a limited set of diagnostics. This facility will be offered to the
FUSENET (the 7th FWP European Fusion Education Network) as a (remote) practica experiment.

Master thesis
S. Malec: Compton camera for detection of hard X-rays produced on the Golem tokamak

MalecMT23

S. Malec. “Compton camera for detection of hard X-rays produced on the Golem tokamak”. Master Thesis. 2023. url: http:
//golem.fjfi.cvut.cz/wiki/Presentations/Students/MasterThesis/23MalecStepan.pdf.
Abstract: This master’s thesis deals with the creation of a Compton camera to detect hard X-rays on the Golem tokamak. First,
simple simulations demonstrating the functionality of a single- and two-sensor Compton camera are introduced. The thesis further
describes the correction of sub- mitted AdvaPix Timepix3 detectors to a phenomenon called timewalk and to cali- bration to
determine the depth of interactions in sensors. The main result is that a single-sensor Compton camera with a CdTe 2 mm thick
sensor shows the best results.
M. Tunkl: Development of a new runaway electron diagnostics method based on strip semiconductor detectors
TunklMT22
M. Tunkl. “Development of a new runaway electron diagnostics method based on strip semiconductor detectors”. Master Thesis.
2022. url: http://golem.fjfi.cvut.cz/wiki/Presentations/Students/MasterThesis/22TunklMarek.pdf.
Abstract: In this master’s thesis, new diagnostics of runaway electrons on the GOLEM tokamak were developed. First, a simulation
in the Geant4 toolkit was created to evaluate the effect of the backscattering of the runaway electrons from the limiter. Then,
a silicon-based strip detector probe was designed and constructed with respect to the simulation result. Finally, the measured
data were analyzed and compared to the relevant diagnostics and simulation results. Furthermore, a new scintillation detector
was constructed from a silicon photomultiplier and a LYSO crystal. The signal from the silicon photomultiplier exhibited good
characteristics. Even with multiple superimposed peaks, it was possible to reconstruct their original height and thus obtain the
hard X-ray spectrum of the entire plasma discharge.
D. Cipciar: Ion and electron temperature study in the edge plasma of the tokamak device

CipciarMT21

D. Cipciar. “Ion and electron temperature study in the edge plasma of the tokamak device”. Master Thesis. 2021. url: http:
//golem.fjfi.cvut.cz/wiki/Presentations/Students/MasterThesis/21DarioCipciar.pdf.
Abstract: This thesis reports on a systematic ion and electron temperature measurements in the scrapeoff layer (SOL) of two
tokamak devices. Results are obtained using a fast swept ball-pen probe with unprecedented temporal resolution (10 jits). Moreover,
an improved analysis technique is presented which increases the amount of relevant data obtained in comparison to previously
published research. The results with high temporal resolution indicate non-Gaussian ion temperature histograms with a peak at
low temperatures and a high temperature tail associated with blobs. The blobs are originating in the vicinity of last closed flux
surface and propagate perpendicularly to the magnetic field lines through the SOL plasma. The resulting fast measurements are
used to simulate the I-V characteristic of a slow swept (3 ms) retarding field analyzer (RFA). The exponential part of the RFA-like
I-V characteristic also determines the ion temperature, but with low temporal resolution (3 ms). The ratios of the ion to electron
temperatures are studied for different plasma densities. We observed that the ratio depends on the line-average plasma density and
it is close to 1-2 in the vicinity of LCFS and 3-4 in the main SOL. A study of the ion temperature fluctuations shows an agreement
with a stochastic model for intermittent turbulence in SOL.
P. Macha: Edge plasma studies in tokamaks by the mean of advanced electric probes.

MachaMT20

P. Macha. “Edge plasma studies in tokamaks by the mean of advanced electric probes.” Master Thesis. 2020. url: http://golem.
fjfi.cvut.cz/wiki/Presentations/Students/MasterThesis/20MachaPetr.pdf.
Abstract: This diploma thesis is dedicated to edge plasma studies in tokamaks by the means of advanced electric probes. After
introduction of the theory and basic concepts of edge plasma physics, electric probes and numerical simulations, the analysis of
probe data from COMPASS and Golem tokamaks is performed. Main focus is given to the fluctuations of plasma parameters and
their respective profiles. A decrease of the level of relative fluctuations of plasma parameters in the velocity shear layer is observed
and the impact of a quasicoherent mode on this decrease is discussed. The electron temperature is determined by the interpolation
of measured tunnel probe current ratio in the scope of a wide parametric scan performed by numerical simulations, resulting in a
high time resolution. This technique is cross-checked by a comparison with established electron temperature measurement methods.
A good agreement between experiment and simulations on the electron side of the tunnel is observed.

B. Leitl: Tomografická rekonstrukce profilu vyzařovánı́ plazmatu na tokamaku Golem

LeitlMT

B. Leitl. “Tomografická rekonstrukce profilu vyzařovánı́ plazmatu na tokamaku Golem”. Master Thesis. 2019. url: http://golem.
fjfi.cvut.cz/wiki/Presentations/Students/MasterThesis/19LeitlBorek.pdf.
Abstract: The thesis is dedicated to the integration of a new diagnostics of plasma radiation detection using AXUV detectors to
the tokamak GOLEM diagnostic system. For two new AXUV20ELG detectors, transimpedance amplifers were constructed, the
detectors calibrated and mounted on the tokamak GOLEM, the first on a small lateral equatorial port and the second upper TOP
port, both on south-east toroidal position. Amplifed signals were digitized by an acquisition system and saved to the GOLEM
database. The tomographic method with Tikhonov regularization using minimization of a Fisher information from the tokamak
COMPASS was adjusted for tokamak GOLEM parameters and used for a data processing.
J. Kocman: Řı́zenı́ polohy plazmatického prstence na tokamaku Golem

KocmanMT

J. Kocman. “Řı́zenı́ polohy plazmatického prstence na tokamaku Golem”. Master Thesis. 2015. url: http://golem.fjfi.cvut.
cz/wiki/Presentations/Students/MasterThesis/15KocmanJindrich.pdf.
Abstract: Determination and control of the plasma position is one of the basic tasks in the tokamak operation. This thesis describes
the current state of the plasma position control on the GOLEM tokamak with a focus on diagnostics for determination of the plasma
position. The theoretical part contains formulae for vertical and horizontal displacement using poloidal magnetic field derived from
Grad–Shafranov equation. The plasma position system is able to control the plasma in two perpendicular directions, the vertical
and the horizontal. It provides two modes, the pre-defined and the feedback. The plasma position system has been implemented
into the remote control room allowing to perform remote plasma position studies. Relative plasma-life prolongation of more than
50% was achieved with this system.
L. Matěna: Microwave interferometry on the tokamak Golem

MatenaMT

L. Matěna. “Microwave interferometry on the tokamak Golem”. Master Thesis. 2015. url: http://golem.fjfi.cvut.cz/wiki/
Presentations/Students/MasterThesis/15MatenaLukas.pdf.
Abstract: After short introduction into nuclear fusion basics the thesis describes the interferometer used at CASTOR tokamak
and basic phenomena necessary to understand its function. The interferometer uses frequency modulation of the diagnostic wave
to eliminate dependence of the output signal on the amplitude of the diagnostic wave. Current status of single components of
the device is than analysed. encountered issues are solved and the interferometer is installed at the Golem tokamak. Two ways of
analysing the output signal are developed (digital and analog) and backup electronic circuitry is made should be old equipment
from CASTOR times fail. Everything is eventually evaluated and the results of individual methods are compared.
Ondřej Ficker: Generation, losses and detection of runaway electrons in tokamaks

FickerMT15

Ondřej Ficker. “Generation, losses and detection of runaway electrons in tokamaks”. Master Thesis. 2015. url: http://golem.
fjfi.cvut.cz/wiki/Presentations/Students/MasterThesis/15FickerOndrej.pdf.
Abstract: This thesis is focused on the so called runaway electrons that are generated in tokamaks under particular conditions.
These energetic electrons are accelerated in the electric field of tokamak almost without collisions with thermal plasma particles
and may cause large damage to the components inside the vacuum vessel. The brief derivation of runaway solution is given in the
thesis and other properties of runaway electrons are summarised. The theoretical relations are subsequently applied to plasmas of
COMPASS and Golem tokamaks. The analysis of data measured on COMPASS is focused namely on the investigation of the link
between the processes of magnetic reconnection during the saw-tooth instability and bursts of runaway electrons. According to the
COMPASS results, the energetic electrons are just ejected and not generated during these phenomena.
T. Markovič: Measurements of magnetic fields on the tokamak Golem.

MarkovicMT12

T. Markovič. “Measurements of magnetic fields on the tokamak Golem.” Master Thesis. 2012. url: http://golem.fjfi.cvut.
cz/wiki/Presentations/Students/MasterThesis/12MarkovicTomas.pdf.
Abstract: In this thesis, a characterization of tokamak Golem magnetic fields and of methods of their measurement is provided.
Specifically, calibration constants and methods of application of magnetic diagnostics on this device are summarized. This includes
not only up-to date detectors of global discharge parameters, but also new detectors for local B theta perturbation studies. Design,
manufacture, calibration and tokamak implementation of the latter diagnostics (refered to as ring coils) is described in detail.
Temperature-resistant state-of-art Hall probes provided by Poznan University of Technology are characterized as well, althought
their tokamak implementation did not take place yet. Measurements of stray fields on tokamak Golem using ring coils suggest,
that main cause of their presence is local saturation of ferromagnetic core, i.e. not currents in tokamak chamber. Measurement
of plasma Btheta by ring coils was found to be less reliable as B theta fluctuation measurement. The latter allows detection and
characterization of plasma MHD structures – the magnetic islands. An investigation of tokamak Golem islands yields that they
change their poloidal rotation frequency by following change in q, most likely due to tendencies to keep constant v theta. For m = 3
islands, v theta approx 0.7 km/s is observed, however for discharges with vertical stabilization horizontal field, island v theta approx
2.0 km/s velocities are typical. Also, model of tokamak Golem magnetic field was developed. Model includes fields by windings of

B phi and external B theta, by tokamak iron core and by tokamak chamber currents. A model of plasma B theta perturbation field
from MHD structures is presented as well.

Bachelor projects
Derap Pena Mukti Sari: The Study of The Hydrogen Plasma Breakdown Phase in The GOLEM Tokamak Reactor
Sari-2024-BachProj
Derap Pena Mukti Sari. “The Study of The Hydrogen Plasma Breakdown Phase in The GOLEM Tokamak Reactor”. Bachelor
project. 2024. url: http : / / golem . fjfi . cvut . cz / wiki / Presentations / Students / FromAbroad / 24DerapPenaMuktiSari English.pdf.
Abstract: The breakdown phase of plasma in a tokamak is a crucial stage before achieving fusion conditions. This stage will influence
the quality of electron production, plasma purity, plasma stability, and more. This study aims to determine the optimum parameters
during the breakdown phase in the GOLEM tokamak by examining the effects of gas pressure and transformer core voltage on
breakdown voltage, discharge duration, and maximum plasma current. The research is conducted remotely using a computer to
access the website connected to the GOLEM tokamak. Eighty discharge data points from the GOLEM tokamak website database
are plotted into graphs. The optimal gas pressure falls within the range of 7-15 mPa. In this pressure range, the discharge duration
(Tdis) and maximum plasma current (Ip, max) reach relatively the highest values (11,59 - 13,56 ms; 2,6 - 3,82 kA). An increase
in the transformer core voltage (UCD) results in an elevation of breakdown voltage (Ubreakdown), discharge duration (Tdis), and
maximum plasma current (Ip, max).
Jan Buryanec: Stabilizace proudu plazmatem na tokamaku Golem

Buryanec-2023-BachProj

Jan Buryanec. “Stabilizace proudu plazmatem na tokamaku Golem”. Bachelor project. 2023. url: http://golem.fjfi.cvut.cz/
wiki/Presentations/Students/BachelorProjects/23BuryanecJan.pdf.
Abstract: This thesis deals with the stabilization of plasma current on tokamak GOLEM. In the theoretical part, the nuclear fusion
and the realization of a fusion reactor in the terrestrial environment is presented. Next, the technologies used on tokamak GOLEM
are described and a research of present generation of plasma current and its possible improvements via the implementation of
the KEPCO am- plifier on the transformer core are done. In the next part, the laboratory table-top experiment simulating the
generation of a plasma current is constructed together with its numerical simulations. For simplification, the vacuum discharge was
used. After the table-top experiment proved the simulations right, the calculations for one KEPCO are done and then, the sole
implementation for tokamak GOLEM. In the end, the testing of a stabilization of current for a given implementation is made and
then, the discussion of a number of KEPCO amplifiers and its effects is done.
M. Vanakova: Studium oscilacı́ magnetického pole na tokamaku Golem

Vanakova-2023-BachProj

M. Vanakova. “Studium oscilacı́ magnetického pole na tokamaku Golem”. Bachelor project. 2023. url: http://golem.fjfi.cvut.
cz/wiki/Presentations/Students/BachelorProjects/23VanakovaMarie.pdf.
Abstract: This bachelor’s thesis deals with tokamak magnetic field configuration. It focuses on the poloidal magnetic field, which
was studied on the GOLEM tokamak. It also presents the safety factor, a parameter defining tokamak magnetic field properties
and characterising particular discharge. The poloidal magnetic field was measured by means of an array of sixteen Mirnov coils for
several tokamak discharges with various plasma edge safety factor values. Measured data was analysed by statistical methods: Fast
Fourier Transformation and Cross-correlation analysis. The presence of magnetic field instabilities (magnetic islands) was observed.
J. Chlum: Implementation of tomographic inversion on the Golem tokamak.

ChlumBP22

J. Chlum. “Implementation of tomographic inversion on the Golem tokamak.” Bachelor project. 2022. url: http://golem.fjfi.
cvut.cz/wiki/Presentations/Students/BachelorProjects/22ChlumJakub.pdf.
Abstract: The topic of this bachelor’s thesis is visible light tomography of tokamak plasma and its implementation on the GOLEM
tokamak. The thesis includes a theoretical summary of radiation processes in tokamak plasmas in the visible spectrum. The thesis
then summarises the principles of the tomography inversion task and its solution with emphasis on the minimum Fisher Tikhonov
regularization algorithm used here. The practical part of the thesis includes the calibration of two fast cameras for the their use
both on the tokamak and separately. The calibration was tested by the tomographic inversion of a known emissivity profile. Finally,
the tomography was tested on experimental data from the GOLEM tokamak. Its limitations and errors were discussed and options
for futher development were suggested.
A. Kubincova: Advanced plasma vertical position reconstruction on the Golem tokamak.

KubincovaBP21

A. Kubincova. “Advanced plasma vertical position reconstruction on the Golem tokamak.” Bachelor project. 2021. url: http:
//golem.fjfi.cvut.cz/wiki/Presentations/Students/BachelorProjects/21KubincovaAdela.pdf.
Abstract: During the tokamak discharge there are usually unwanted movements of the plasma ring. We measure these using
diagnostics and filters which remove noise from the measured data. Kalman filter (KF) is such a filter. It can very effectively remove
the noise and predict values of the observable based on a model. In this thesis we shall derive such model for vertical movement of

plasma on the Golem tokamak. The model does not include the influence of control coils, however, we suggest a way to incorporate
this effect. In the process we determined the time constant of the vessel and we measured for the first time the time constant of
the shell to be 15.46 ms. This measurement agrees with the theoretical computation and it is higher than estimated. In the end we
give recommendations for measurement of vertical position of plasma on the Golem tokamak using the KF.
J. Malinak: Electron temperature measurements using rail probe on the tokamak Golem.

MalinakBP21

J. Malinak. “Electron temperature measurements using rail probe on the tokamak Golem.” Bachelor project. 2021. url: http:
//golem.fjfi.cvut.cz/wiki/Presentations/Students/BachelorProjects/21MalinakJiri.pdf.
Abstract: This bachelor thesis is devoted to the problem of measurement of edge plasma parameters with a new type of probe,
the so-called rail probe. The advantage of this probe is that thanks to its design it can withstand extremely high heat fluxes and
at the same time behaves as a proud Langmuir probe for a certain non-zero angle of incident field lines. The thesis summarises
the fundamental physics of the Langmuir probe and sheath expansion. A manipulator was developed and constructed to allow
tilting of the probe head, which includes a proud Langmuir probe and a ball-pen probe in addition to the rail probe. Comparative
measurements of the electron temperature using all of these probes are presented and show conformity. The dependence of the
obtained plasma parameters on the head tilt angle is also investigated. The measured data are compared with a 2D PIC simulation
performed for a Golem tokamak. These 2D PIC simulations will be an essential part of the rail probe’s development for the
COMPASS Upgrade tokamak.
F. Papousek: Impact of swept edge plasma potential biasing on turbulence in tokamaks.

PapousekBP20

F. Papousek. “Impact of swept edge plasma potential biasing on turbulence in tokamaks.” Bachelor project. 2020. url: http:
//golem.fjfi.cvut.cz/wiki/Presentations/Students/BachelorProjects/20PapousekFilip.pdf.
Abstract: In the tokamak plasma the edge plasma is the barrier between the hot confined plasma centre and the cold tokamak
vessel. One of the fastest mechanisms of energy and particle loss from the confined plasma is turbulent transport. One of the
concepts to understand turbulence and its self–organization are zonal flows, further referred to as ZFs. ZFs have two branches,
near-zero frequency flows and geodesic acoustic modes further referred to as GAMs with higher frequency(typically tens of kHz on
most tokamaks of modest size and regular aspect ratio). The symmetry and stability of ZFs cause the energy of turbulence to flow
out and thus, ZFs cause saturation of drift–wave turbulence.
P. Macha: Měřenı́ parametrů plazmatu pomocı́ kombinované ball-pen a langmuirovy sondy na tokamaku Golem.
MachaBP18
P. Macha. “Měřenı́ parametrů plazmatu pomocı́ kombinované ball-pen a langmuirovy sondy na tokamaku Golem.” Bachelor project.
2018. url: http://golem.fjfi.cvut.cz/wiki/Presentations/Students/BachelorProjects/18MachaPetr.pdf.
Abstract: The bachelor thesis is dedicated to the edge plasma parameters measurements and ball-pen probe calibration at the
Golem tokamak. The first part introduces the theory of plasma and the physics of tokamaks, focusing on the Golem tokamak. The
next part presents basic diagnostics of the Golem tokamak. The second part covers the physical principles of both Langmuir and
ball-pen probes and the theory important for planned meassurements. Finally, the description of experimental set-ups probes at
the Golem tokamak and experimental set-ups are given. The third part describes the experimental results obtained in hydrogen
and helium plasmas. Based on the data, ball-pen probe calibration is determined and basic plasma parameters are evaluated. These
results are finally presented and compared for both working gases. The thesis is concluded with the overal discussion and summary
of all the achieved results.
T. Okonechnikova: Prezentace tokamaku Golem pomocı́ technologie X3DOM

OkonechnikovaBP

T. Okonechnikova. “Prezentace tokamaku Golem pomocı́ technologie X3DOM”. Bachelor project. 2016. url: http://golem.fjfi.
cvut.cz/wiki/Presentations/Students/BachelorProjects/16OkonechnikovaTatiana.pdf.
Abstract: The bachelor thesis deals with 3D virtual world integration into the web page using X3DOM technology. Web interface
implements important interactive functions to control the virtual world. It allows to work independently of the platform. The result
of the project is a web application that introduces students of Physics and Technology of Thermonuclear Fusion with the tokamak
Golem.
B. Leitl: Bolometrická měřenı́ na tokamaku Golem

LeitlBP

B. Leitl. “Bolometrická měřenı́ na tokamaku Golem”. Bachelor project. 2014. url: http : / / golem . fjfi . cvut . cz / wiki /
Presentations/Students/BachelorProjects/14LeitlBorek.pdf.
Abstract: The bachelor thesis is devoted to the description of properties of fast AXUV diodes and its practical application for the
detection of plasma radiated power in UV and Soft-X-ray region at the tokamak Golem. Plasma position is fixed from fitting simple
and double Gaussian curve to the measured data and the theory of symmetric Abel inversion is also analysed in the thesis, because
it enables to display 2D profile of radiated power and its time resolution. Bolometric plasma diagnostics was put into operation on
the tokamak Golem for test AXUV module and it is now possible to install two brand new detectors.

J. Veverka: Studium počátečnı́ fáze výboje v tokamacı́ch

VeverkaBP

J. Veverka. “Studium počátečnı́ fáze výboje v tokamacı́ch”. Bachelor project. 2014. url: http://golem.fjfi.cvut.cz/wiki/
Presentations/Students/BachelorProjects/14VeverkaJakub.pdf.
Abstract: The start-up phase of a discharge is the most important part of an experiment. It determines its success or failure.
Effective generation if plasma in tokamak devices can be dependable on various parameters, e.g. working gas pressure, intensity of
toroidal magnetic field or type of preionization. Optimization of the Avalanche ionization phase is therefore an important part of
fusion research. This work summarises the principles of nuclear fusion reactions along with the history of development of controlled
nuclear fusion. Afterwards, principles of a magnetic confinement of plasma in tokamak devices are described, together with the
description of Golem tokamak, where the experiments were performed. In following parts, data that characterize the start-up phase
of discharge are examined and presented, related to the type of preionization and values of discharge parameters (working gas
pressure, intensity of electric and magnetic field). Short separate part is dedicated to interesting results using ECRH preionization
(electron cyclotron resonance heating).
M. Matušů: Virtual model of tokamak Golem with real physical core

MatusuBP

M. Matušů. “Virtual model of tokamak Golem with real physical core”. Bachelor project. 2014. url: http://golem.fjfi.cvut.
cz/wiki/Presentations/Students/BachelorProjects/14MatusuMartin.pdf.
Abstract: Thermonuclear fusion is a potential energy source for next few centuries. In order to control this process on Earth,
it is necessary to simulate conditions of Sun core. All matter is in plasma state in these conditions and therefore a thermonuclear reactor is needed to create a environment for the plasma. Requirements on such a reactor are stated in Lawson criterion.
Tokamak device is except other types of thermonuclear reactor close to meet Lawson criterion. This device uses a strong closed
magnetic field to confine plasma within reactor vessel. On the other hand, this set-up brings technical difficulties of the whole
experiment. A lot of small tokamaks, which cannot meet fusion conditions, were build for a purpose of material and diagnostics
testing. One of them is a Golem tokamak operating as an educational device at the Faculty of Nuclear Sciences and Physical
Engineering of the Czech Technical University in Prague. One of the most important functions of this tokamak is a discharge
remote control via web interface. This specification set the main idea of a creation of a virtual model, which would give user
more specific conception of the real tokamak. In order to make the model easy accessible, internet environment has been chosen
again. Graphical elements of model were placed on the web with the use of a library WebGL. Such a model was extended by
a physical core of simulations, reflecting back at the graphical model. The whole program is accessible on the Golem server at:
http://golem.fjfi.cvut.cz/virtual/matusu/BachelorThMM/BMM.html.
R. Duban: Měřenı́ rychlosti toku plazmatu na tokamaku Golem pomocı́ pole Machových sond.

DubanBP

R. Duban. “Měřenı́ rychlosti toku plazmatu na tokamaku Golem pomocı́ pole Machových sond.” Bachelor project. 2014. url:
http://golem.fjfi.cvut.cz/wiki/Presentations/Students/BachelorProjects/14DubanRichard.pdf.
Abstract: Poloidal asymmetry of edge plasma flow speed is one of current topics of high-temperature plasma physics. This experiment
on Golem tokamak allows us to measure flow speed distribution of edge plasma along the magnetic field lines with unique spatial
resolution. This thesis describes basic concepts of plasmaphysics, thermonuclear fusion and basic principles of tokamak operation.
Mean theme contains measurement of parameters of magnetized plasma with Langmuir and Mach probes. Experimental part of
this thesis contains analysis of edge plasma flow speed having regard of its poloidal distribution.
J. Kocman: Zpětnovazebnı́ řı́zenı́ polohy na tokamaku Golem.

KocmanBP

J. Kocman. “Zpětnovazebnı́ řı́zenı́ polohy na tokamaku Golem.” Bachelor project. 2011. url: http://golem.fjfi.cvut.cz/wiki/
Presentations/Students/BachelorProjects/11KocmanJindrich.pdf.
Abstract: Determination and control of plasma column position play an important role in the operation of a tokamak. Stabilization
of the plasma position in the Golem tokamak needs to be reinstalled after relocation to the FNSPE CTU. The theoretical part of
this thesis contains formulae for vertical and horizontal displacement and the asymmetry factor (Shafranov parameter). This part
also includes the derivation of the Grad-Shafranov equation and the resulting condition for the vertical magnetic field needed to
stabilize the plasma position in the direction of the major radius. In the experimental part two methods for the determination of
vertical position in the Golem tokamak are compared. The first one was derived in the theoretical part, the second one was used for
the Golem tokamak in the past. Moreover, the horizontal displacement as a function of the external stabilizing vertical magnetic
field was measured. The first results show an effect on the horizontal position. The final part of the thesis comprises a discussion
about possible causes of a phenomenon which appears in discharges with long plasma life.
O. Pluhař: Interactive model of tokamak Golem.

PluharBP

O. Pluhař. “Interactive model of tokamak Golem.” Bachelor project. 2011. url: http://golem.fjfi.cvut.cz/wiki/Presentations/
Students/BachelorProjects/11PluharOndrej.pdf.
Abstract: Tokamak Golem is a useful piece of laboratory equipment on the grounds of Faculty of Nuclear Sciences and Physical
Engineering of Czech Technical University in Prague. The main aim of this project is to create an interactive virtual world with
tokamak Golem inside accessible online for public. This virtual world contains rich information of the tokamak from its visual

appearance to basic functionality. Tokamak Golem has not been transferred into virtual environment before; therefore this project
will be a great asset to students and professors in learning how the device works even before they go hands-on with the actual
equipment. Virtual Reality Modeling Language (VRML) was used as a project requirement.
T. Markovič: Magnetic field configurations and their measurement on tokamak Golem.

MarkovicBP

T. Markovič. “Magnetic field configurations and their measurement on tokamak Golem.” Bachelor project. 2010. url: http :
//golem.fjfi.cvut.cz/wiki/Presentations/Students/BachelorProjects/10MarkovicTomas.pdf.
Abstract: Basic overview of configurations of magnetic field in a tokamak, along with means of its measurement is provided.
Since most common magnetic diagnostics sensors presently used are of inductive nature, pros and cons of two main concepts of
analog integration are discussed. As galvanometric sensors such as Hall probes have been getting more attention lately as they
do not require integration, characterization of these sensors is included. Along with description of magnetic field configurations
on tokamak Golem, discussion concerning present state of its magnetic diagnostics with proposals of its modification is included
as well. Extension of reliability range of Mirnov coils used for local magnetic field measurements is demonstrated on two different
experiments. In the first experiment, modeling of poloidal magnetic field gives insight into permeability of chamber. The other
experiment is aimed on first approximation of plasma column position with simple use of local magnetic field sensors. Additionally,
a method of toroidal magnetic field cross-talk elimination in signal of poloidal magnetic field sensors is described.

High School Students‘ Professional Activities
M. Pokorný: Měřenı́ a simulace polohy plazmatu na tokamaku GOLEM

pokorSOC23

M. Pokorný. “Měřenı́ a simulace polohy plazmatu na tokamaku GOLEM”. High School Students‘ Professional Activities SOČ. 2023.
url: http://golem.fjfi.cvut.cz/wiki/Presentations/Students/HighSchoolActivities/23PokornyPolohaPlazmatu.pdf.
Abstract: The first part of this work focuses on plasma position measurement, the second on its simulation. In the first part, we
compare all available plasma position diagnostics at the GOLEM (CTU FNSPE) tokamak, i.e., Mirnov coils, a ball-pen probe, and
a high-speed camera. Mirnov coils and high-speed camera data were mostly in accord; the plasma boundary is more clearly defined
in the case of Mirnov coils, the camera registers visible plasma radiation in the order of 1 mm beyond the real plasma boundary.
Ball-pen probe and camera data mostly weren’t in accord; the ball-pen probe is effective only in the case of local plasma boundary
measurement. On the basis of our comparison we recommend: Mirnov coils usage is appropriate when conducting a detailed plasma
position analysis, ball-pen probe usage is appropriate for local measurements, and high-speed camera usage is appropriate for quick
but imprecise measurements. In the second part of the work, we put into operation the static inverse and static direct regimes of
the NICE code (B. Faugeras, 2020) for the GOLEM tokamak. For this intent, a virtual GOLEM model is created, which makes use
of the toroidally symmetrical iron core model presented in (T. Markovič, 2013). It is shown, on the basis of measurement and NICE
simulation comparison, that the value of magnetic induction running through the real and virtual iron cores differs by a factor of
approximately 2. Regimes that have been put into operation are illustrated with concrete simulations, and it is shown that their
results are in accordance with typical GOLEM plasma configurations. For quick and easy usage of these regimes, a graphical user
interface is created.
E. Pumprlová: Vliv tlaku pracovnı́ho plynu na generaci ubı́hajı́cı́ch elektronů v tokamaku Golem.

pumprSOC

E. Pumprlová. “Vliv tlaku pracovnı́ho plynu na generaci ubı́hajı́cı́ch elektronů v tokamaku Golem.” High School Students‘ Professional Activities SOČ. 2022. url: http://golem.fjfi.cvut.cz/wiki/Presentations/Students/HighSchoolActivities/
22PumprlovaRunaaways.pdf.
Abstract: This study investigates how working gas pressure affects the generation of runaway electrons in the tokamak Golem. The
aim is to describe this relationship and the course of runaway electron generation in tokamak. The theoretical framework of this
study inquiries into the topic of runaway electrons, the practical part tests a hypothesis: in low pressure plasma the number of
runaway electrons is going to be greater than in plasma of higher pressure. The experimental part also includes the data analysis,
which portrays the course of generation of runaway electrons. Scintillation detectors were used to collect the data, the analysis of
values measured was conducted in the programming language Python. The experiment confirmed the hypothesis and the results
opened new subjects to study more closely.
M. Pokorný: Sondová měřenı́ parametrů okrajového plazmatu na tokamaku Golem s pomocı́ motorizovaného
manipulátoru
pokorSOC22
M. Pokorný. “Sondová měřenı́ parametrů okrajového plazmatu na tokamaku Golem s pomocı́ motorizovaného manipulátoru”.
High School Students‘ Professional Activities SOČ. 2022. url: http://golem.fjfi.cvut.cz/wiki/Presentations/Students/
HighSchoolActivities/22PokornyProbes.pdf.
Abstract: This SOC thesis focuses on the measurement of edge plasma parameters using electrical probes at the Golem tokamak.
In the theoretical part of the work, a basis for understanding plasma and its behavior is given and some general principles of
thermonuclear fusion and tokamaks are presented. Finally, a theoretical basis for the measurement of edge plasma parameters by
electrical probes is provided with an accent on the double tunnel probe. The practical part of the work first focuses on the process

of putting into operation a new motorized probe manipulator and its application at the Golem tokamak. Moreover, the course and
results of experimental measurements with the double tunnel probe are presented. Within two discharge series, we were able to
measure axial profiles of ion saturated current thanks to the new motorized manipulator. Firstly, a calibration of the probe was done
and axial profiles of ion saturated current were measured. Afterwards, measurements and calculations of parallel and perpendicular
components of the Mach number of plasma rotation were performed. Furthermore, the time dependence of the parallel component
of the Mach number in a parallel probe orientation to magnetic field lines was measured. Finally, two methods of calculation of the
Mach number related to the axial profiles of ion saturated current were compared. The data received from ion saturated current
axial profiles and Mach number measurements is in accordance with the results of multiple articles related to this topic.
A. Socha: Poloha zóny vytvářenı́ turbulentnı́ch struktur v okrajovém plazmatu tokamaku Golem

sochaSOC

A. Socha. “Poloha zóny vytvářenı́ turbulentnı́ch struktur v okrajovém plazmatu tokamaku Golem”. High School Students‘ Professional Activities SOČ. 2021. url: http://golem.fjfi.cvut.cz/wiki/Presentations/Students/HighSchoolActivities/
21Socha_sikmostIsat.pdf.
Abstract: This work deals with the study of turbulent structures in the edge plasma of the Golem tokamak. The main goal of this
work was to find the place of origin of turbulent structures. Plasma turbulence, and associated turbulent structures, are important
for maintaining energy in the tokamak. The hypothesis is that in the marginal plasma there is a zone of turbulent structure
formation, where the number of blobs and holes is the same, and which is firmly connected to the plasma edge - separatrix. It is
this question that deals with the experimental part of this work, in which I wanted to confirm or refute this hypothesis. I searched
for the zone of creating turbulent structures by measuring the radial slope profile. To check the measured data and at the same
time to predict the measured values, I created a script in the Python programming language, thanks to which reconstructions of
the plasma position in the poloidal section of the chamber, including the position of the probe, can be plotted. Unfortunately, the
results of this work did not find a place of turbulent structures for technical reasons (limited length of the probe manipulator). On
the other hand, the measured results indicate the presence of positive turbulent structures (blobs) on the outside of the separatrix,
which is in line with the assumed theory.
M. Lauerová: Měřenı́ elektronové teploty na tokamaku Golem elektrickými sondami

lauerSOC

M. Lauerová. “Měřenı́ elektronové teploty na tokamaku Golem elektrickými sondami”. High School Students‘ Professional Activities SOČ. 2021. url: http://golem.fjfi.cvut.cz/wiki/Presentations/Students/HighSchoolActivities/21Lauerova_
ElTeplota.pdf.
Abstract: In this work I focus on the analysis of the tokamak edge plasma, a key area of interest on the path to commercial
thermonuclear fusion. The study of the edge plasma is important because it dictates the interactions between the extremely hot
plasma in the middle where all the fusion reactions occur and the vessel (it describes heat interactions and erosions of the vessel
walls). I compare two methods of measuring the electron temperature using electric probes. My specific goal is to prove that the new
and innovative combined method using a ball-pen probe and a Langmuir probe performs as well as the widely used swept Langmuir
probe. I consider this analysis to be important because the combined probe method is much easier and less time consuming. Also,
it measures with wider accruals, therefore it is possible to identify various turbulent structures.
P. Skála: Termojaderná fúze a experiment s vysokoteplotnı́m plazmatem

skalaSOC

P. Skála. “Termojaderná fúze a experiment s vysokoteplotnı́m plazmatem”. High School Students‘ Professional Activities SOČ.
2021. url: http://golem.fjfi.cvut.cz/wiki/Presentations/Students/HighSchoolActivities/21Skala-sondy.pdf.
Abstract: Obecné fungovánı́ tokamaků. Diagnostika a princip zı́skávánı́ dat pomocı́ tokamaku Golem. Experimentálnı́ část: měřenı́
parametrů plazmatu pomocı́ sond BPP a DRP.
D. Kropáčková: Stabilizace plazmatu na tokamaku Golem

danySOC20

D. Kropáčková. “Stabilizace plazmatu na tokamaku Golem”. High School Students‘ Professional Activities SOČ. 2020. url: http:
//golem.fjfi.cvut.cz/wiki/Presentations/Students/HighSchoolActivities/20Kropackova_Stabilizace.pdf.
Abstract: The aim of this work is plasma stabilization on GOLEM tokamak. In this thesis is also described the measurement of
plasma position and measurement of vertical magnetic field.
M. Horák: Profil elektronové teploty v komoře tokamaku

horakSOC

M. Horák. “Profil elektronové teploty v komoře tokamaku”. High School Students‘ Professional Activities SOČ. 2020. url: http:
//golem.fjfi.cvut.cz/wiki/Presentations/Students/HighSchoolActivities/20Horak_ElTeplota.pdf.
Abstract: Thesis focuses on the topic of the thermonuclear fusion and description of plasma development by defined global parameters. It explains the basic principles of tokamak’s operation and clarifies problems for plasma maintaining. In addition, to this the
thesis concentrates on measurement and development of electron temperature in tokamak chamber, depending on the distance of
the probe from the centre of the chamber.

D. Kropáčková: Měřenı́ rotace plazmatu dvojitou tunelovou sondou na tokamaku Golem

danySOC19

D. Kropáčková. “Měřenı́ rotace plazmatu dvojitou tunelovou sondou na tokamaku Golem”. High School Students‘ Professional Activities SOČ. 2019. url: http://golem.fjfi.cvut.cz/wiki/Presentations/Students/HighSchoolActivities/19Kropackova_
RotacePLazmatu.pdf.
Abstract: The aim of this work is the measurement of the Mach number and the determination of the plasma rotation direction at
tokamak GOLEM depending on the orientation of the magnetic and electric fields.
M. Grof: Poloidálnı́ rotace plazmatu na tokamaku Golem

grofSOC

M. Grof. “Poloidálnı́ rotace plazmatu na tokamaku Golem”. High School Students‘ Professional Activities SOČ. 2014. url: http:
//golem.fjfi.cvut.cz/wiki/Presentations/Students/HighSchoolActivities/14Grof_RotacePlazmatu.pdf.
Abstract: Plazma je nedı́lnou součástı́ našeho vesmı́ru. Jeho pochopenı́ nám pomůže lépe pochopit, jak vznikl náš vesmı́r, a umožnı́
nám rozvoj nových technologiı́, zejména zdroj energie – termojaderná fúze, což je proces ve hvězdách. Tokamak GOLEM patřı́
mezi nejstaršı́ funkčnı́ tokamaky, ale neustále je na něm co zkoumat. Z pohledu magnetohydrodynamických studiı́ lze zjistit mnoho
důležitých informacı́ o struktuře a pohybu plazmatu. Jednou z nich je rotace v poloidálnı́m směru, kterou se zde zabývám.
M. Cvan: Termojaderná Fúze

cvanSOC

M. Cvan. “Termojaderná Fúze”. High School Students‘ Professional Activities SOČ. 2013. url: http://golem.fjfi.cvut.cz/
wiki/Presentations/Students/HighSchoolActivities/13Cvan_Fuze.pdf.
Abstract: The aim of my long-term thesis is to introduce high school students to the basic physical aspects of thermonuclear devices,
particularly tokamaks. In the theoretical part, there is the basic knowledge necessary for getting this simpliest idea of tokamak
operation. The practical part describes experiments that I made on the tokamak Golem in Prague.
O. Grover: Měřenı́ hustoty plazmatu interferometrickou metodou na Tokamaku Golem.

groverSOC

O. Grover. “Měřenı́ hustoty plazmatu interferometrickou metodou na Tokamaku Golem.” High School Students‘ Professional Activities SOČ. 2011. url: http://golem.fjfi.cvut.cz/wiki/Presentations/Students/HighSchoolActivities/11Grover_
HustotaPlazmatu.pdf.
Abstract: Měřenı́ hustoty plazmatu na základě šı́řenı́ elektromagnetických vln v plazmatu. Využitı́ modulace k umožněnı́ zpracovanı́
dat.

Miscellaneous
The Golem Tokamak contributors: Magnetic confinement of high temperature plasma at the Golem tokamak
GMhandson
The Golem Tokamak contributors. Magnetic confinement of high temperature plasma at the Golem tokamak. http://golem.fjfi.
cvut.cz/wiki/Education/GMinstructions/extracts/GeneralHandsOn/docum.pdf. [Online; accessed 2-January-2020]. 2020.
Abstract: This assignment introduces students to the physics, technology, diagnostics and operation of the Golem tokamak. It
comprises performing a tokamak experiment and exploring the basic scaling properties of magnetic plasma confinement.
Huang et al.: Global Tokamak Experiment

GTE2010

B. Huang and V. Nikolaeva. Global Tokamak Experiment. http://tokamakglobal.com/. 2010.
ITER news: Launch of the world’s first global tokamak experiment

iternews

ITER news. Launch of the world’s first global tokamak experiment. http://www.iter.org/newsline/156/512. 2010.
Jan Mlynář: Golem history

GolemHistory

Jan Mlynář. Golem history. http://golem.fjfi.cvut.cz/wiki/History/Articles/GolemHistoryHM.pdf. [Online; accessed
2-January-2019]. 2010.
Abstract: Golem history since 1960.
Tokamak Golem contributors: Tokamak Golem at the Czech Technical University in Prague

Golem2007

Tokamak Golem contributors. Tokamak Golem at the Czech Technical University in Prague. http://golem.fjfi.cvut.cz. 2007.

Unofficial articles (without GOLEM cooperation/authors)
Chandrasekaran et al.: Magnetohydrodynamic Mode Identification for Golem Mirnov Coil Signals Using Singular
Value Decomposition and Multichannel Variational Mode Decomposition Method for Analyzing Time-Frequency
ChandrasekarJFE22
J. Chandrasekaran and S. Jayaraman. “Magnetohydrodynamic Mode Identification for Golem Mirnov Coil Signals Using Singular
Value Decomposition and Multichannel Variational Mode Decomposition Method for Analyzing Time-Frequency”. In: Journal of
fusion energy 41.2 (Dec. 2022). issn: 0164-0313. doi: 10.1007/s10894-022-00329-5.
Abstract: In this paper, we have investigated the method to study non-stationary signal characteristics in plasma tokamak using
the combination of Multichannel Variational Mode Decomposition (MVMD) and Singular Value Decomposition (SVD). We have
applied this technique directly without any signal preprocessing techniques over the Mirnov coil signals to analyze the magnetic
fluctuations produced by the rotating magnetic fields of the plasma in tokamaks. Extraction of Principal axes (PA) and Principal
Components (PC) of multichannel Mirnov coil signals are through the singular value decomposition technique. The Multichannel
variational mode decomposition technique is provided with a PC matrix to identify the dominant harmonics as K-modes. Finally,
the Time-frequency analysis is carried out using Hilbert Transform (HT). The proposed technique handles multichannel Mirnov coil
signals in parallel to frequency identification, and also to understand the poloidal structure during current perturbation. Artificially
simulated data and Mirnov coil signals from Golem Tokamak aided in testing the proposed technique. In Golem data during the
present rise phase, transition happens in the current perturbation from m = 4, poloidal structures to m = 3, and m = 2. The
simulated data and Golem tokamak data generated the results of the proposed model. The article also compared this with other
existing signal decomposition techniques.
Chandrasekar et al.: Data-driven disruption prediction in Golem Tokamak using ensemble classifiers
Chandrasekar20
J. Chandrasekar, S. Madhawa, and J. Sangeetha. “Data-driven disruption prediction in Golem Tokamak using ensemble classifiers”.
In: Journal of Intelligent & Fuzzy Systems 39 (2020), pp. 8365–8376. doi: 10.3233/JIFS-189155.
Abstract: A robust disruption prediction system is mandatory in a Tokamak control system as the disruption can cause malfunctioning of the plasma-facing components and impair irrecoverable structural damage to the vessel. To mitigate the disruption, in
this article, a data-driven based disruption predictor is developed using an ensemble technique. The ensemble algorithm classifies
disruptive and non-disruptive discharges in the Golem Tokamak system. Ensemble classifiers combine the predictive capacity of
several weak learners to produce a single predictive model and are utilized both in supervised and unsupervised learning. The
resulting final model reduces the bias, minimizes variance and is unlikely to over-fit when compared to the individual model from
a single algorithm. In this paper, popular ensemble techniques such as Bagging, Boosting, Voting, and Stacking are employed on
the time-series Tokamak dataset, which consists of 117 normal and 70 disruptive shots. Stacking ensemble with REPTree (Reduced
Error Pruning Tree) as a base learner and Multi-response Linear Regression as meta learner produced better results in comparison
to other ensembles. A comparison with the widely employed stand-alone machine learning algorithms and ensemble algorithms are
illustrated. The results show the excellent performance of the Stacking model with an F1 score of 0.973. The developed predictive
model would be capable of warning the human operator with feedback about the feature(s) causing the disruption.
Faridyousefi et al.: MHD Mode Identification from Mirnov Coils Signals in Tokamak Via Combination of Singular
Value Decomposition and Hilbert–Huang Transform Analysis Methods
Faridyousefi20
H. Faridyousefi, M. Salem, and M. Ghoranneviss. “MHD Mode Identification from Mirnov Coils Signals in Tokamak Via Combination of Singular Value Decomposition and Hilbert–Huang Transform Analysis Methods”. In: Journal of Fusion Energy 39 (2020),
pp. 1–9. doi: 10.1007/s10894-020-00273-2.
Abstract: In this work, we investigate how to study the MHD activities in Tokamak plasma via the combination of singular value
decomposition (SVD) and Hilbert–Huang transform (HHT) methods. We apply this approach to the Mirnov coil signal fluctuations
analysis without any filtering technique. First, the principal axes (PAs) of a pick-up Mirnov signals are extracted by SVD analysis.
Next, the harmonics of dominants PAs is obtained by empirical mode decomposition (EMD) analysis. Moreover, the time-frequency
behavior of Mirnov signals are extracted by HHT. The proposed technique is employed to analyze Mirnov coils signals for mode type
and frequency identification, especially in multimode MHD activities. We obtained Spatial–temporal structures of the Mirnov coils
fluctuations in terms of correlation functions to better identification of mode number and frequencies of dominant MHD modes.
We also present the results of this method applied to IR-T1 and Golem Tokamaks Mirnov coils signals. Consequently, satisfying
results from SVD + HHT analysis method and spatial-temporal structures for IR-T1 and Golem Tokamaks Mirnov data observed.