Nonlinear evolution of double tearing mode with guiding magnetic field

作者：Zhang C L; Ma Z W^*

来源：Physics of Plasmas, 2011, 18(5): 052303.

DOI：10.1063/1.3581064

Nonlinear dynamic evolution of the double tearing mode (DTM) with a guiding magnetic field (B(y0)) is investigated by magnetohydrodynamical numerical simulation. The dynamic process of DTM depends weakly on the guiding field in the weak guiding field regime (B(y0) <= 1), but is suppressed by a strong guiding field (B(y0) > 2). During the explosive nonlinear phase, the maximum reconnection rate (gamma(max)) increases weakly with the increase of the resistivity as gamma(max) eta(0.06) for B(y0) <= 1, but for B(y0) > 2, gamma(max) is nearly independent of the resistivity. The maximum reconnection rate in the explosive growth phase increases with increase of the initial current sheet separation. A secondary tearing instability is observed at moderate current sheet separation. A strong guiding field suppresses the formation of a secondary island. Based on the simulation results, it is found that the secondary tearing instability occurs only when the length-to-thickness aspect ratio of the reconnection region exceeds about 20.

• 出版日期2011-5
• 单位浙江大学