高磁雷诺数下剪切流对双撕裂模中二级磁岛的影响

在高磁雷诺数下，当双撕裂模发展进入快速磁场重联阶段时，会发生二级磁岛不稳定性，加剧磁场能量的释放。本文基于扰动形式的守恒磁流体方程组发展高精度的数值模拟程序，在平板位形下研究反对称位形剪切流对双撕裂模中二级磁岛的影响。结果表明：随着剪切流强度和剪切梯度的增加，二级磁岛的数目以及电流片横纵比变小。此外，较强的极向剪切流能够抑制二级磁岛不稳定性的发生。

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

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.