National Institute for Fusion Science;
Toki 509-5292;
Japan;
The Graduate University for Advanced Studies;
SOKENDAI;
Toki 509-5292;
Japan;
Institute for Plasma Research;
Gandhinagar 382428;
India;
Graduate School of Frontier Science;
The University of Tokyo;
Kashiwa 277-8561.Japan;
Naka Fusion Institute;
National Institutes for Quantum and Radiological Science and Technology;
Naka 311-0193;
Japan;
Institute of Advanced Energy;
Kyoto University;
Uji 611-0011;
Japan;
tomography; Laplacian eigenfunction; Heliotron J; soft x-ray;