Nonresonant suppression of the sawtooth instability by passing ions in tokamaks

Lazaros, A

dc.contributor.author	Lazaros, A	en
dc.date.accessioned	2014-03-01T01:16:48Z
dc.date.available	2014-03-01T01:16:48Z
dc.date.issued	2001	en
dc.identifier.issn	1070-664X	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/14233
dc.subject.classification	Physics, Fluids & Plasmas	en
dc.subject.other	STABILIZATION	en
dc.subject.other	JET	en
dc.subject.other	SAWTEETH	en
dc.title	Nonresonant suppression of the sawtooth instability by passing ions in tokamaks	en
heal.type	journalArticle	en
heal.identifier.primary	10.1063/1.1377860	en
heal.identifier.secondary	http://dx.doi.org/10.1063/1.1377860	en
heal.language	English	en
heal.publicationDate	2001	en
heal.abstract	A new interpretation is presented for the well-known observation of sawteeth stabilization, during ion cyclotron resonant heating, in the Joint European Tokamak [Campbell et al., Phys. Rev. Lett. 60, 2148 (1988)] and the Tokamak Fusion Test Reactor [Phillips et al., Phys. Fluids B 4, 2155 (1992)]. It is shown that the radial fluxes of superthermal and thermal ions exchange a finite amount of power with the m = 1 mode (associated with the sawtooth instability) which is suppressed. The dominant contribution to this effect is provided by the passing ions, which experience in the presence of the mode a much faster (than the trapped ions) radial diffusion. This is a nonresonant electrostatic interaction between the passing ions and the finite parallel electric field (along the perturbed magnetic field line), which takes place at any mode frequency. For the requirements of the present theory, the concepts of the finite parallel electric field, and the diffusion of passing ions, in the presence of a magnetic mode are also developed. The present work also provides the interpretation for the suppression of the sawtooth instability by passing ions, during tangential neutral beam injection, in the Japan Atomic Energy Research Institute Tokamak Upgrade (JT-60U) [Kramer et al., Nucl. Fusion 40, 1383 (2000)]. © 2001 American Institute of Physics.	en
heal.publisher	AMER INST PHYSICS	en
heal.journalName	Physics of Plasmas	en
dc.identifier.doi	10.1063/1.1377860	en
dc.identifier.isi	ISI:000169930900021	en
dc.identifier.volume	8	en
dc.identifier.issue	8	en
dc.identifier.spage	3695	en
dc.identifier.epage	3701	en