Two‐dimensional spatial distribution of volume emission from line integral data

• Published in: Review of scientific instruments 1981-11, Vol.52 (11), p.1634-1643
• Main Authors: Navarro, A. P., Paré, V. K., Dunlap, J. L.
• Format: Article
• Language: English
• ISSN: 0034-6748; 1089-7623
• DOI: 10.1063/1.1136510

A method is presented for determining the two‐dimensional (2‐D) spatial distribution of the volume emission intensity [E = f(r,ϑ)] in a plasma from line integral data obtained by arrays of collimated detectors looking through the plasma along different chords. Subject to the assumption that E can be represented by J m  [f m (r)cos mϑ +g m (r)sin mϑ] with only a few terms m, expressions are developed that separate harmonic contributions to the line integrals, a numerical procedure is outlined for inversion of these contributions to obtain the factors f m (r) and g m (r), and the formulas that result are presented for m = 0 through m = 5. This method was developed for application to data from arrays of soft x‐ray detectors on the Impurity Study Experiment (ISX‐B) tokamak. One use would be comparison of the soft x‐ray volume emission contours with other measures of plasma shape. Simulations of these shape determinations were performed, using as input, a pressure profile representing a calculated MHD equilibrium for a D‐shaped plasma in ISX‐B. The results of these simulations are shown and the determination of the poloidal structure of MHD perturbations in the plasma is also illustrated.