Li Z, Wang X Q, Xu Y, Liu H F, Huang J
Institute of Fusion Science, School of Physical Science and Technology Southwest, Jiaotong University, Chengdu, 610031, China.
Sci Rep. 2023 Aug 21;13(1):13559. doi: 10.1038/s41598-023-40920-0.
The nonlinear interaction between the double tearing mode (DTM) and Kelvin-Helmholtz (KH) instabilities with different shear flow profiles has been numerically investigated via the use of a compressible magnetohydrodynamics (MHD) model. We focus on KH instabilities in weak and reversed magnetic shear plasmas with strong stabilizing effect of field line bending. Results show that KH instabilities coupled with DTMs occur in these plasmas and the KH mode dominates the instability dynamics, suggesting the crucial role of weak magnetic shear in the formation of high-mode harmonics. For symmetric flows, an asymmetric forced magnetic reconnection configuration is maintained during the growth phase, leading to interlocking of the modes. Additionally, this investigation of the DTM-KH instability interaction contributes to our understanding of the nonlinear reconnection mechanism in the regime of weak and reversed magnetic shear plasmas, which is relevant for astrophysical and fusion studies.
通过使用可压缩磁流体动力学（MHD）模型，对具有不同剪切流剖面的双撕裂模（DTM）与开尔文 - 亥姆霍兹（KH）不稳定性之间的非线性相互作用进行了数值研究。我们关注在具有磁力线弯曲强稳定作用的弱磁剪切和反磁剪切等离子体中的KH不稳定性。结果表明，在这些等离子体中会出现与DTM耦合的KH不稳定性，并且KH模主导了不稳定性动力学，这表明弱磁剪切在高模谐波形成中起着关键作用。对于对称流，在增长阶段会维持一种不对称的强迫磁重联构型，导致模式的相互锁定。此外，对DTM - KH不稳定性相互作用的这项研究有助于我们理解弱磁剪切和反磁剪切等离子体区域中的非线性重联机制，这与天体物理和聚变研究相关。
