Do magnetospheric shear Alfvén waves generate sufficient electron energy flux to power the aurora
Do magnetospheric shear Alfvén waves generate sufficient electron energy flux to power the aurora
复制标题
磁层剪切阿尔芬波是否会产生足够的电子能量通量来为极光提供动力
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
R. Rankin
中科院分区：
文献类型：
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作者：
C. Watt;R. Rankin
[1]使用自洽漂移动力学模拟代码，我们调查是否由于剪切阿尔芬波在等离子体片边界层的电子加速是足以导致极光增亮的电离层。模拟代码中使用的自由参数是由距地球>4 RE距离的磁层中的波和等离子体参数的现场观测所指导的。对于研究中使用的垂直波长（在110公里高度映射到104公里），有一个明确的振幅阈值，它决定了经典极光加速区上方的磁层剪切阿尔芬波是否能激发足够的电子来产生极光。以前的研究报告的波振幅很容易超过这个阈值，因此，本文报告的结果表明，由于剪切阿尔芬波的极光加速可以发生在距离地球>4 RE的磁层。
[1] Using a self-consistent drift-kinetic simulation code, we investigate whether electron acceleration owing to shear Alfven waves in the plasma sheet boundary layer is sufficient to cause auroral brightening in the ionosphere. The free parameters used in the simulation code are guided by in situ observations of wave and plasma parameters in the magnetosphere at distances >4 RE from the Earth. For the perpendicular wavelength used in the study, which maps to ∼4 km at 110 km altitude, there is a clear amplitude threshold which determines whether magnetospheric shear Alfven waves above the classical auroral acceleration region can excite sufficient electrons to create the aurora. Previous studies reported wave amplitudes that easily exceed this threshold; hence, the results reported in this paper demonstrate that auroral acceleration owing to shear Alfven waves can occur in the magnetosphere at distances >4 RE from the Earth.