@misc{oai:repo.qst.go.jp:00083797,
 author = {Yuji, Shimabukuro and Junichi, Hiratsuka and Masahiro, Ichikawa and Masamichi, Murayama and mae quinones Saquilayan, Glynnis and Masashi, Kisaki and Atsushi, Kojima and Hiroyuki, Tobari and Mieko, Kashiwagi and Yuji, Shimabukuro and Junichi, Hiratsuka and Masahiro, Ichikawa and Masamichi, Murayama and mae quinones Saquilayan, Glynnis and Masashi, Kisaki and Atsushi, Kojima and Hiroyuki, Tobari and Mieko, Kashiwagi},
 month = {Sep},
 note = {Protection system of cathodes from local discharge has been developed for the high power and stable negative ion source used in the heating system of ITER and JT-60SA. Discharge marks on the cathode indicate that this discharge occurs not only to anode walls but also plasma, so-called unipolar discharge. The critical issue is that the local discharge increases with cesium seedings to enhance the negative ions. To minimize damage on the cathode, a fast cut-off system of discharge current has been developed by combining Field Programmable Gate Array (FPGA) and IGBT switch and was applied to protect the filament cathode in the large negative ion source with 1.2 m long. Growth rate of local discharge was independent of the discharge power and varied from 150 to 400 mA/μs. However, local discharge with an energy less than 1.3 J did not cause remarkable damage on the filaments, corresponding to the cut-off time of 280 μs. This system can be applied to any cathode in the ion sources., International Conference on Ion Sources 2021},
 title = {Suppression of damages on cathodes in the negative hydrogen ion source for the stable NBI system},
 year = {2021}
}