Hits:

Indexed by:Journal Papers

Date of Publication:2020-01-01

Journal:PHYSICS OF PLASMAS

Included Journals:EI、SCIE

Volume:27

Issue:1

ISSN No.:1070-664X

Abstract:Effects of sub-Alfvenic shear flows on the complicated properties of three types of unstable eigenmodes, namely, coupled triple tearing mode (M-1), coupled double tearing mode (M-2), and three single tearing modes (M-3), in a triple current sheet configuration are studied by means of an eigenvalue analysis. It is identified that the difference of velocity among three resonant surfaces rather than the local flow shear rate plays the more important role in the three types of eigenmodes. Thus, it is found that for the symmetric shear flow (SSF), the growth rate of the M-1/M-3 mode decreases/increases with the increasing strength of the shear flow, while the growth rate of the M-2 mode is almost uninfluenced by SSF. For the antisymmetric shear flow (ASF), it is interestingly observed that in the small wavenumber regime, the M-1 and M-2 modes degenerate into similar eigenmode states with the same growth rate and opposite traveling frequencies. In the large wavenumber regime, the M-2 and M-3 modes degenerate into similar eigenmode states. Moreover, for both SSF and ASF, the growth rates of the three types of modes are almost the same in the small and large wavenumber limits.