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P: Fachverband Plasmaphysik

P 19: Poster II

P 19.22: Poster

Donnerstag, 31. März 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.