Optimization of soft X-ray tomography on the COMPASS tokamak

0464277 - ÚFP 2017 RIV PL eng J - Článek v odborném periodiku
Imríšek, Martin - Mlynář, Jan - Löffelmann, Viktor - Weinzettl, Vladimír - Odstrčil, T. - Odstrčil, M. - Tomeš, Matěj
Optimization of soft X-ray tomography on the COMPASS tokamak.
Nukleonika. Roč. 61, č. 4 (2016), s. 403-408. ISSN 0029-5922. E-ISSN 1508-5791.
[Summer School of Plasma Diagnostics PhDiaFusion 2015: “Soft X-ray Diagnostics for Fusion Plasma”. Bezmiechowa, 16.06.2015-20.06.2015]
Grant CEP: GA MŠMT(CZ) LM2011021; GA MŠMT LG14002; GA MŠMT(CZ) 8D15001
GRANT EU: European Commission(XE) 633053 - EUROfusion
Institucionální podpora: RVO:61389021
Klíčová slova: soft X-ray * tomography * Tikhonov regularization * tokamak
Kód oboru RIV: BL - Fyzika plazmatu a výboje v plynech
Impakt faktor: 0.760, rok: 2016
http://www.ichtj.waw.pl/nukleonikaa/?p=1256

The COMPASS tokamak is equipped with the soft X-ray (SXR) diagnostic system based on silicon photodiode arrays shielded by a thin beryllium foil. The diagnostic is composed of two pinhole cameras having 35 channels each and one vertical pinhole camera with 20 channels, which was installed recently to improve tomographic inversions. Lines of sight of the SXR detectors cover almost complete poloidal cross section of the COMPASS vessel with a spatial resolution of 1–2 cm and temporal resolution of about 3 micro s. Local emissivity is reconstructed via Tikhonov regularization constrained by minimum Fisher information that provides
reliable and robust solution despite limited number of projections and ill-conditionality of this task. Improved border conditions and numerical differentiation matrices suppressing artifacts in reconstructed radiation were implemented in the code. Furthermore, a fast algorithm eliminating iterative processes was developed, and it is foreseen to be tested in real-time plasma control.
Trvalý link: http://hdl.handle.net/11104/0263423