Bolometric images of the three-dimensional structure of asymmetric radiative collapse in LHD

The infrared (IR) imaging bolometer has the merit of being able to measure wide two-dimensional images of the plasma radiation. Two IR imaging video bolometers (IRVB, one type of IR imaging bolometer system) were installed on the large helical device (LHD). Using these IRVBs, the asymmetric radiation collapse that is similar to the multifaceted asymmetric radiation from the edge was measured in LHD. From the results of the asymmetric collapse study in LHD, the high radiation region is localized on the inboard side and under the midplane on the vacuum vessel, but this region is not the nearest point from the plasma to the first wall. From other reports on LHD, it is written that the wall recycling is not a trigger for the asymmetric radiation onset, which is confirmed by this new result.