Link to the meeting in Microsoft Teams: https://tiny.pl/c1f96

Abstract

The Radiated Power and Soft X-ray Core Intensity diagnostic under development aims to measure the SXR photons generated by DEMO plasma. The primary role of the diagnostics is to measure the radiation profiles of the plasma and to provide the plasma core radiated power needed to calculate the power crossing the separatrix using radiation tomography reconstruction. This contribution covers the development of numerical algorithms within the framework of the radiation tomography reconstruction problem. The task of tomography is to reconstruct the spatial distribution of plasma radiation intensity on the basis of measurements of external detectors recording the cumulative effect from a given direction. The planar radiation intensity distribution in the plasma section is the primary image for the pinhole transformation of the detection system. Proposed method of reconstructing the radiation distribution in a given plasma cross-section assumes a linear model of planar distribution described by a set of data base functions. Considerations of the reconstruction of the plasma emissivity in the tokamak take into account the dependencies related to the magnetic field. Plasma properties are assumed to be constant at the magnetic flux surfaces and can be represented as 1D profiles depending on the poloidal magnetic flux. In the reconstruction of the plasma emissivity distribution using the approximation method, three sets of base functions were considered: polynomials and Gaussian functions with sigma and position parameters. The approximation method tests were carried out for the reconstruction of two radiation power emission phantoms. The reconstruction error of the two simulated Gauss and Hollow distributions is a function of the number of detectors and was close to 1%, which gives hope for a reliable recognition of the actual distributions of plasma intensity in the tokamak.

References:
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