Development of large-current long-pulse negative ion beams for JT-60SA negative ion source

Kojima, Atsushi; Hanada, Masaya; Yoshida, Masafumi; Kashiwagi, Mieko; Tobari, Hiroyuki; Umeda, Naotaka; Watanabe, Kazuhiro; NB Heating Technology Group

Recent activities on the new test stand are reported toward demonstration of the long pulse production for 22A, 100s negative ion beams. As for the temperature control of the plasma grid, a prototype of the grid with cooling/heating by circulating a high-temperature fluorinated fluid has been developed. This grid was found to have a capability to control the temperature with a time constant of 10s by considering the physical properties of the fluid. Based on this result, new PG temp-control system has been developed with all extraction area. In the preliminary results, 22A beam for 10s has been achieved.