Effect of Shear Flow on Secondary Magnetic Islands in DTM at High Magnetic Reynolds Numbers

doi:10.19596/j.cnki.1001-246x.8235

Abstract

Abstract:

At high magnetic Reynolds numbers, as double tearing modes develop into rapid magnetic reconnection phase secondary magnetic island instability occurs, which intensifies the release of magnetic field energy. We developed a high-precision numerical simulation program based on perturbed conservative MHD equation. Effect of antisymmetric shear flow on second-order magnetic islands in double tearing modes was studied in a plane configuration. It shows that the number of secondary magnetic islands and current-sheet aspect ratio both decrease with the increase of shear flow velocity and gradient of shear flow velocity. In addition, a strong polar shear flow inhibits the occurrence of secondary magnetic island instability.

Key words: secondary magnetic island, shear flow, high magnetic Reynolds number, conserved MHD equation

CLC Number:

O534⁺.2

Yao TAN. Effect of Shear Flow on Secondary Magnetic Islands in DTM at High Magnetic Reynolds Numbers[J]. Chinese Journal of Computational Physics, 2021, 38(3): 343-351.

Figures/Tables 9

Fig.1 Time evolution of logarithmic kinetic energy

Fig.2 Magnetic flux at different times

Fig.3 (a) Current density and (b) streamlines of plasma velocity (t= 46)

Fig.4 (a) Current density and (b) streamlines of plasma velocity (t= 48) at beginning of the secondary magnetic island formation

Fig.5 (a) Current density and (b) streamlines of plasma velocity (t=50) of a fully developed secondary magnetic island

Fig.6 Profiles of equilibrium magnetic field and shear flow

Fig.7 Numbers of secondary island and current-sheet aspect ratios for different shear flow profiles

Fig.8 Magnetic flux and plasma velocity streamlines of a fully developed secondary magnetic island

Fig.9 Magnetic flux of a fully developed secondary magnetic island under different shear flow

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