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format: markdown
title: Electron temperature measurements by electric probes
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# Supervisors

Main supervisor:

* Name: Ing. Kateřina Jiráková
* Rank: PhD student in the 2nd year, a minion to Vojtěch Svoboda
* Contact: katerina.jirakova@fjfi.cvut.cz 

Assistant supervisor:

* Name: Bc. Petr Mácha
* Rank: Master's student in the last year, working hard on his Master's thesis
* Contact: machap11@fjfi.cvut.cz

# Introduction 

In edge plasma physics, electric probes are invaluable instruments. Easy to build and notorically hard to interpret, they provide measurements of the electron temperature, density and energy distribution function; they can even measure the plasma potential, all with great spatial and temporal resolution. The basic drawback of probes is threefold: they can only be used in low-parameter plasma, they may disturb the plasma and their measurement is valid only as far as you believe probe theory (that is to say, it's complicated).

In this assignment, you will work with the so-called [petiprobe](/Diagnostics/ParticleFlux/PetiProbe/index), a combined probe head consisting of a [ball-pen probe, Langmuir probe](/Diagnostics/ParticleFlux/BallPenProbe/index) and [two tunnel probes](/Diagnostics/ParticleFlux/TunnelProbe/index). The probe can measure electron temperature in three distinct ways:

* floating ball-pen and Langmuir probe [[Adámek, RSI 2016]](https://aip.scitation.org/doi/10.1063/1.4945797)
* ion saturation current from the tunnel probe [[Gunn, RSI 2004]](https://aip.scitation.org/doi/10.1063/1.1787581)
* swept Langmuir probe [[Merlino, AJP 2007]](https://aapt.scitation.org/doi/10.1119/1.2772282)

Your task will be to use the first two methods and compare their results.

# Task description

In this assignment you will:

* be introduced to probe theory in tokamak plasmas
* perform a series of discharges on the GOLEM tokamak while making measurements with the petiprobe
* process the experimental data to calculate the $T_e$ profiles
* compare the $T_e$ profiles and discuss their similarities/differences
* write a report on your findings and give a presentation

#  Requirements 

* basic knowledge of Python (if you are proficient at data processing in another programming language, you can go ahead and use that, but I won't be able to help you very much)
* basic knowledge of tokamaks
* being well-rested, healthy and ready for several days of hard mental work

You don't need to know much about probes in advance because we'll be explaining everything anyway.

# Useful links and literature

* [J. Wesson, *Tokamaks*, Oxford University Press 2011](https://www.youtube.com/watch?v=dQw4w9WgXcQ)