Mainz 2022 – scientific programme
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P: Fachverband Plasmaphysik
P 19: Poster II
P 19.22: Poster
Thursday, March 31, 2022, 16:00–17:30, P
Validating soft X-ray tomograms via modeling of perturbative events — •Christian Brandt1, Henning Thomsen1, Charlotte Büschel2, Edith V. Hausten2, Jonathan Schilling1, René Bussiahn1, and and the W7-X Team1 — 1Max-Planck-Institute for Plasma Physics, Greifswald, Germany — 2University Greifswald, Germany
The hot core of a fusion plasma is invisible in the visual part of the spectrum but it radiates strongly in the X-ray range. A soft X-ray (SX) tomography system detects the spatiotemporal structure of the core plasma in a poloidal cross-section at the stellarator experiment Wendelstein 7-X. Depending on the presence of localized structures on top of the background X-ray radiation profile, such as injected impurity pellets, injected cryogenic hydrogen pellets or MHD mode structures, the poloidal cross-sectional SX emissivity can be substantially structured. The validity of the tomograms obtained by tomographic inversion with respect to the real topology of the SX emissivity is benchmarked by forward calculations of different modeled perturbation scenarios (e.g. symmetric vs. asymmetric 2-D emissivity, local blobs, mode structures). More parameters sensitively influencing the quality of the tomographic inversion are investigated, i.e. the signal-to-noise ratio and the amplitude calibration.