Electron kinetic effects in standing shear Alfvén waves in the dipolar magnetosphere
Electron kinetic effects in standing shear Alfvén waves in the dipolar magnetosphere
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DOI：
10.1063/1.874105
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发表时间：
2000-05
影响因子：
2.2
通讯作者：
V. Tikhonchuk;R. Rankin
中科院分区：
文献类型：
--
作者：
V. Tikhonchuk;R. Rankin
在偶极几何的情况下，考虑了驻切Alfven波(SAW)驱动的电流对电子的动力学响应。由电子回转运动方程和声表面波色散系数得到了平行电场。在偶极磁场中的电子俘获显著降低了平行电导率，从而增加了平行电场的幅度和SAW色散。结果表明，在电子反弹频率大于声表面波频率的情况下，许多作者使用的双流体流体动力学方程大大低估了电子的响应，从而低估了平行电场的大小和位置。这在地球极地磁层附近密度凹陷的等离子体中尤为重要。
The electron kinetic response to an electric current driven by a standing shear Alfven wave (SAW) is considered for the case of a dipolar geometry. The parallel electric field is found from the electron gyrokinetic equation along with the SAW dispersion coefficient. Electron trapping in the dipolar magnetic field significantly reduces the parallel electric conductivity and in this way increases the amplitude of the parallel electric field and SAW dispersion. It is demonstrated that the two-fluid hydrodynamic equations used by many authors significantly underestimate the electron response and, consequently, the magnitude and location of the parallel electric field under conditions where the electron bounce frequency is larger than the SAW frequency. This is especially important in a plasma with density depressions near the Earth’s polar magnetosphere.