Model of inductive plasma production assisted by radio-frequency wave in Tokamaks

Makoto Hasegawa, Kazuaki Hanada, Kohnosuke Sato, Kazuo Nakamura, Hideki Zushi, Mizuki Sakamoto, Hiroshi Idei, Shoji Kawasaki, Hisatoshi Nakashima, Aki Higashijima

Research output: Contribution to journalArticlepeer-review


For initial plasma production, an induction electric field generated by applying voltage to a poloidal field (PF) coil system is used to produce a Townsend avalanche breakdown. When the avalanche margins are small, as for the International Thermonuclear Experimental Reactor (ITER) in which the induction electric field is about 0.3 V/m, the assistance of radio-frequency waves (RF) is provided to reduce the induction electric field required for reliable breakdown. However, the conditions of RF-assisted breakdown are not clear. Here, the effects of both RF and induction electric field on the RF-assisted breakdown are evaluated considering the electron loss. When traveling loss is the dominant loss, a simple model of an extended Townsend avalanche is proposed. In this model, the induction electric field required for RF-assisted breakdown can be decreased to half that required for induction breakdown.

Original languageEnglish
Article number084501
Journaljournal of the physical society of japan
Issue number8
Publication statusPublished - Aug 2007

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


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