E??×??B flow shear drive of the linear low-n modes of EHO in the QH-mode regime

doi:10.1088/1741-4326/aa7975

	E??×??B flow shear drive of the linear low-n modes of EHO in the QH-mode regime
	Xu,G.S.2,3; Wan,B.N.2; Wang,Y.F.2,3; Wu,X.Q.2; Chen,Xi 1; Martin Peng,Y.-K.3; Guo,H.Y.1,2; Burrell,K.H.1; Garofalo,A.M.1; Osborne,T.H.1
刊名	Nuclear Fusion
	2017-07-18
卷号	57
关键词	E??×??B flow shear QH-mode EHO low-n kink/peeling mode DIII-D
ISSN号	0029-5515
DOI	10.1088/1741-4326/aa7975
英文摘要	Abstract A new model for the edge harmonic oscillations (EHOs) in the quiescent H-mode regime has been developed, which successfully reproduces the recent observations in the DIII-D tokamak. In particular, at high E??×??B flow shear only a few low-n kink modes remain unstable at the plasma edge, consistent with the EHO behavior, while at low E??×??B flow shear, the unstable mode spectrum is significantly broadened, consistent with the low-n broadband electromagnetic turbulence behavior. The model is based on a new mechanism for destabilizing low-n kink/peeling modes by the E??×??B flow shear, which underlies the EHOs, separately from the previously found Kelvin–Helmholtz drive. We find that the differential advection of mode vorticity by sheared E??×??B flows modifies the 2D pattern of mode electrostatic potential perpendicular to the magnetic field lines, which in turn causes a radial expansion of the mode structure, an increase of field line bending away from the mode rational surface, and a reduction of inertial stabilization. This enhances the kink drive as the parallel wavenumber increases significantly away from the rational surface at the plasma edge where the magnetic shear is also strong. This destabilization is also shown to be independent of the sign of the flow shear, as observed experimentally, and has not been taken into account in previous pedestal linear stability analyses. Verification of the veracity of this EHO mechanism will require analysis of the nonlinear evolution of low-n kink/peeling modes so destabilized in the linear regime.
语种	英语
出版者	IOP Publishing
WOS记录号	IOP:0029-5515-57-8-AA7975
内容类型	期刊论文
源URL	[http://ir.hfcas.ac.cn:8080/handle/334002/43003]
专题	中国科学院合肥物质科学研究院
作者单位	1.General Atomics, PO Box 85608, San Diego, CA 92186-5608, United States of America 2.Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People’s Republic of China 3.University of Science and Technology of China, Hefei 230026, People’s Republic of China
推荐引用方式 GB/T 7714	Xu,G.S.,Wan,B.N.,Wang,Y.F.,et al. E??×??B flow shear drive of the linear low-n modes of EHO in the QH-mode regime[J]. Nuclear Fusion,2017,57.
APA	Xu,G.S..,Wan,B.N..,Wang,Y.F..,Wu,X.Q..,Chen,Xi.,...&Li,J..(2017).E??×??B flow shear drive of the linear low-n modes of EHO in the QH-mode regime.Nuclear Fusion,57.
MLA	Xu,G.S.,et al."E??×??B flow shear drive of the linear low-n modes of EHO in the QH-mode regime".Nuclear Fusion 57(2017).