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P: Fachverband Plasmaphysik
P 6: Poster Session - Diagnostics
P 6.6: Poster
Montag, 2. März 2015, 16:30–18:30, Foyer Audimax
Non-thermal electron energy distributions in microwave heated plasmas measured with electron cyclotron emission — •Severin Denk1,2, Rainer Fischer2, Ulrich Stroth1,2, Omar Maj2, Emanuele Poli2, Egbert Westerhof3, Matthias Willensdorfer2, Jörg Stober2, and The ASDEX-Upgrade Team2 — 1Physik-Department E28, Technische Universität München, 85747 Garching, Germany — 2Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching, Germany — 3FOM Institute DIFFER - Dutch Institute for Fundamental Energy Research, Nieuweigein, The Netherlands
The electron cyclotron emission diagnostic (ECE) provides routinely electron temperature measurements Te. However, the determination of Te from the measured radiation temperature profile Trad is hampered if the plasma is not optically thick, or if non-thermal electron energy distributions (EEDF) occur. At ASDEX Upgrade an electron cyclotron forward model (ECFM) exists, that solves the radiation transport equation for given Te and electron density profiles. The ECFM was extended with a non-thermal absorption coefficient to support also non-thermal EEDFS. Furthermore, all non-relativistic approximations were removed from the ECFM. For thermal plasmas the latter allowed an improved description of Trad at the plasma edge. Additionally, it could be shown via the forward model that in plasmas with large Te shine-through effects can appear at the plasma core. The sensitivity of the ECE on non-thermal EEDFs was studied via parametrized EEDFs and Fokker-Planck EEDFs.