Ma Z W, Chen T, Zhang H W, Yu M Y
Institute for Fusion Theory and Simulation, Department of Physics, Zhejiang University, Hangzhou, 310027, China.
Sci Rep. 2018 Jul 12;8(1):10521. doi: 10.1038/s41598-018-28851-7.
An effective resistivity relevant to collisionless magnetic reconnection (MR) in plasma is presented. It is based on the argument that pitch angle scattering of electrons in the small electron diffusion region around the X line can lead to an effective, resistivity in collisionless plasma. The effective resistivity so obtained is in the form of a power law of the local plasma and magnetic field parameters. Its validity is confirmed by direct collisionless particle-in-cell (PIC) simulation. The result agrees very well with the resistivity (obtained from available data) of a large number of environments susceptible to MR: from the intergalactic and interstellar to solar and terrestrial to laboratory fusion plasmas. The scaling law can readily be incorporated into existing collisional magnetohydrodynamic simulation codes to investigate collisionless MR, as well as serve as a guide to ab initio theoretical investigations of the collisionless MR process.
提出了一种与等离子体中无碰撞磁重联（MR）相关的有效电阻率。它基于这样的观点：在X线周围的小电子扩散区域中，电子的俯仰角散射可导致无碰撞等离子体中的有效电阻率。如此获得的有效电阻率呈局部等离子体和磁场参数的幂律形式。通过直接的无碰撞粒子模拟（PIC）证实了其有效性。结果与大量易发生磁重联的环境（从星系际和星际到太阳和地球再到实验室聚变等离子体）的电阻率（从现有数据获得）非常吻合。该标度律可以很容易地纳入现有的碰撞磁流体动力学模拟代码中，以研究无碰撞磁重联，也可作为无碰撞磁重联过程的从头算理论研究的指南。
