Hannover 2016 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 12: Poster Session: Magnetic Confinement
P 12.1: Poster
Dienstag, 1. März 2016, 16:30–19:00, Empore Lichthof
Electron cyclotron emission measurements at the stellarator TJ-K — •Gabriel Sichardt1, Alf Köhn2, and Mirko Ramisch1 — 1Institut für Grenzflächenverfahrenstechnik und Plasmatechnologie, Universität Stuttgart — 2Max-Planck-Institut für Plasmaphysik, Garching
Electron temperature (Te) measurements in the magnetised plasmas of the stellarator TJ-K are currently performed by means of Langmuir probes. The use of these probes is restricted to relatively low temperatures and the measurement of temperature profiles requires the acquisition of the local current-voltage characteristics which limits strongly the sampling rate. As an alternative, Te can be measured using the electron cyclotron emission (ECE) that is generated by the gyration of electrons in magnetised plasmas. Magnetic field gradients in the plasma lead to a spatial distribution of emission frequencies and thus the measured intensity at a given frequency can be related to its point of origin. The Te dependence of the intensity then leads to a temperature profile along the line of sight for Maxwellian velocity distributions. A diagnostic system for Te measurements using ECE is currently being set up at TJ-K.
When non-thermal electrons are present the emission spectrum changes dramatically. Therefore, the ECE can also be used to investigate the contribution of fast electrons to previously observed toroidal net currents in TJ-K. Simulations are used to examine the role of electron drift orbits in generating these currents.