Nishimura K, Sanpei A, Tanaka H, Ishii G, Kodera R, Ueba R, Himura H, Masamune S, Ohdachi S, Mizuguchi N
Department of Electronics, Kyoto Institute of Technology, Kyoto 606-8585, Japan.
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan.
Rev Sci Instrum. 2014 Mar;85(3):033502. doi: 10.1063/1.4867076.
We have developed a two-dimensional (2D) electron temperature (T(e)) diagnostic system for thermal structure studies in a low-aspect-ratio reversed field pinch (RFP). The system consists of a soft x-ray (SXR) camera with two pin holes for two-kinds of absorber foils, combined with a high-speed camera. Two SXR images with almost the same viewing area are formed through different absorber foils on a single micro-channel plate (MCP). A 2D Te image can then be obtained by calculating the intensity ratio for each element of the images. We have succeeded in distinguishing T(e) image in quasi-single helicity (QSH) from that in multi-helicity (MH) RFP states, where the former is characterized by concentrated magnetic fluctuation spectrum and the latter, by broad spectrum of edge magnetic fluctuations.
