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title: Density measurements by microwave interferometer
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# Task outline

* Learn the basics of microwave interferometry at the GOLEM tokamak
* Learn digital data processing routines for calculating the electron density 
    * choose one algorithm from Fourier transform, 0-crossing, Hilbert transform
* Perform experiments focusing on electron density $n_e$:
    * $n_e$ dependence on discharge parameters .. i.e. how to achieve target $n_e(t)$
    * dependance of other discharge characteristics on different $n_e(t)$ 

# Resources

* [Diploma thesis by Lukas Matena](http://golem.fjfi.cvut.cz/wiki/Diagnostics/Basic/ElectronDensity/instructions/15MatenaLukas.pdf) includes:
    * basic theory of plasma interferometry, MW propagation in plasma
    * analog analysis circuit development
    * comparison of digital algorithms based on the Fourier transform and 0-crossing

* [Overview page with links to more resources](http://golem.fjfi.cvut.cz/wiki/Diagnostics/Basic/ElectronDensity/index)

* Example $n_e$ calculation via the Fourier transform: [signal demodulation page](http://golem.fjfi.cvut.cz/shots/18685/diagnostics/Microwaves/0712Interferometer.ON/01_Demodulated%20signal.php) and the responsible [Python code](http://golem.fjfi.cvut.cz/shots/18685/diagnostics/Microwaves/0712Interferometer.ON/main.py)

* Example and explanation of a generalized algorithm based on the Hilbert transform and comparison with the original one: [folder](/TrainingCourses/PlasmaSchools/GOMTRAIC.cz/19/tasks/interferometry/)