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Indexed by:期刊论文

Date of Publication:2017-04-01

Journal:NUCLEAR FUSION

Included Journals:SCIE、EI

Volume:57

Issue:4

ISSN No.:0029-5515

Key Words:tokamaks; magnetic reconnection; tearing modes; plasma rotation

Abstract:The control of neo-classical tearing modes (NTMs) by the differential rotation in the reversed magnetic shear (RMS) configuration with different separations Delta r(s) between two rational surfaces is numerically studied by means of reduced magnetohydrodynamic (MHD) simulations. It is found that the differential rotation with a strong shear at the outer resonant surface can effectively suppress the explosive burst of double tearing modes (DTMs)/NTMs. Critical values of the strength of rotation to suppress the burst are also presented for different bootstrap current fractions f(b). Furthermore, a couple of measurable parameters (delta, kappa), corresponding respectively to the triangularity and elongation of the magnetic islands at the outer resonant surface, are introduced to characterize the deformation of islands in the nonlinear phase. It is found that the triangularity delta is more likely to precisely predict the onset of burst than the island width w and elongation kappa. For a given Delta r(s), the critical value of triangularity delta(crit) is obtained by scanning different plasma parameters. Establishing such a database of (delta, kappa) is helpful to effectively control the development of NTMs in the RMS experimental discharges.