Hannover 2016 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 26: Poster Session-Plasma Diagnostics

P 26.4: Poster

Donnerstag, 3. März 2016, 16:30–19:00, Empore Lichthof

Investigation of the influence of plasma temperature on Doppler reflectometry — •Vandana Revathi Venkateswaran, Carsten Lechte, and Thomas Hirth — IGVP, University of Stuttgart

Doppler reflectometry is a microwave scattering diagnostic technique which employs the scattering of waves near plasma cutoffs to get information on the electron density fluctuations and also poloidal flows in toroidal fusion experiments. The scattering process has to be investigated using simulation codes in order to interpret the diagnostic results. In this case, the influence of temperature on reflectometry is studied and discussed. IPFs Finite-Difference Time Domain method based code called IPF-FD3D is used to study the fluctuations. For the warm plasmas as opposed to cold plasmas,where the plasmas have values of electron temperature similar to those of existing tokamaks relativistic effects might also be important. A mass correction makes the cold-plasma approximation in agreement with that of the fully relativistic theory (for a range of values that is the only one of interest for X-mode reflectometry in tokamaks). This makes us modify the codes related to the cold plasma theory of wave propagations applicable to cases of plasmas with characteristics similar to those of existing tokamaks [1]. The method is incorporated to study its influence on cutoffs and scattering efficiency. Initial results will be presented.

[1] E. Mazzucato, Phys. Fluids B 4, 3460 (1992).