Electron-cyclotron wave propagation, absorption and current drive in the presence of neoclassical tearing modes

Isliker, H; Chatziantonaki, I; Tsironis, C; Vlahos, L

dc.contributor.author	Isliker, H	en
dc.contributor.author	Chatziantonaki, I	en
dc.contributor.author	Tsironis, C	en
dc.contributor.author	Vlahos, L	en
dc.date.accessioned	2014-03-01T02:08:51Z
dc.date.available	2014-03-01T02:08:51Z
dc.date.issued	2012	en
dc.identifier.issn	07413335	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/29731
dc.subject.other	Axisymmetric	en
dc.subject.other	Current drives	en
dc.subject.other	Electron cyclotrons	en
dc.subject.other	Flux surfaces	en
dc.subject.other	Magnetic equilibrium	en
dc.subject.other	Magnetic island	en
dc.subject.other	Neoclassical tearing modes	en
dc.subject.other	Power deposition	en
dc.subject.other	Ray-tracing codes	en
dc.subject.other	Resonant particles	en
dc.subject.other	Tokamak plasmas	en
dc.subject.other	Toroidal geometry	en
dc.subject.other	Wave evolution	en
dc.subject.other	Computational geometry	en
dc.subject.other	Cyclotron radiation	en
dc.subject.other	Magnetoplasma	en
dc.subject.other	Plasma waves	en
dc.subject.other	Topology	en
dc.subject.other	Electron beams	en
dc.title	Electron-cyclotron wave propagation, absorption and current drive in the presence of neoclassical tearing modes	en
heal.type	journalArticle	en
heal.identifier.primary	10.1088/0741-3335/54/9/095005	en
heal.identifier.secondary	http://dx.doi.org/10.1088/0741-3335/54/9/095005	en
heal.identifier.secondary	095005	en
heal.publicationDate	2012	en
heal.abstract	We analyze the propagation of electron-cyclotron waves, their absorption and current drive when neoclassical tearing modes (NTMs), in the form of magnetic islands, are present in a tokamak plasma. So far, the analysis of the wave propagation and power deposition in the presence of NTMs has been performed mainly in the frame of an axisymmetric magnetic field, ignoring any effects from the island topology. Our analysis starts from an axisymmetric magnetic equilibrium, which is perturbed such as to exhibit magnetic islands. In this geometry, we compute the wave evolution with a ray-tracing code, focusing on the effect of the island topology on the efficiency of the absorption and current drive. To increase the precision in the calculation of the power deposition, the standard analytical flux-surface labeling for the island region has been adjusted from the usual cylindrical to toroidal geometry. The propagation up to the O-point is found to be little affected by the island topology, whereas the power absorbed and the driven current are significantly enhanced, because the resonant particles are bound to the small volumes in between the flux surfaces of the island. The consequences of these effects on the NTM evolution are investigated in terms of the modified Rutherford equation. © 2012 IOP Publishing Ltd.	en
heal.journalName	Plasma Physics and Controlled Fusion	en
dc.identifier.doi	10.1088/0741-3335/54/9/095005	en
dc.identifier.volume	54	en
dc.identifier.issue	9	en