Nonthermal electrons at high Mach number shocks: Electron shock surfing acceleration
Nonthermal electrons at high Mach number shocks: Electron shock surfing acceleration
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DOI：
10.1086/340454
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发表时间：
2002-06-20
影响因子：
4.9
通讯作者：
Shimada, N
中科院分区：
文献类型：
--
作者：
Hoshino, M;Shimada, N
我们通过使用细胞内粒子模拟来研究高马赫数状态下垂直磁声冲击波中的超热电子加速机制。我们发现，产生超热电子的激波冲浪/表面加速器加速发生在激波转变区，在反射离子和入射电子之间的相互作用下，布尼曼不稳定性激发了一系列大振幅静电孤立波（ESW）。结果表明，电子很可能被ESWs捕获，并且在捕获阶段，它们可以被激波运动/对流电场有效地加速。我们讨论超热电子可以加速到 m(i)c(2) (v(0)/c)，其中 m(i)c(2) 是离子静止质量能，v(0) 是激波上游流速。此外，当阿尔文马赫数M-A超过几十时，其中一些超热电子可能被有效地捕获无限长的时间，并且它们被加速到由全局激波大小决定的激波势能。
We study the suprathermal electron acceleration mechanism in a perpendicular magnetosonic shock wave in a high Mach number regime by using a particle-in-cell simulation. We find that shock surfing/surfatron acceleration producing suprathermal electrons occurs in the shock transition region, where a series of large-amplitude electrostatic solitary waves ( ESWs) are excited by Buneman instability under the interaction between the reflected ions and the incoming electrons. It is shown that the electrons are likely to be trapped by ESWs, and during the trapping phase they can be effectively accelerated by the shock motional/convection electric field. We discuss that suprathermal electrons can be accelerated up to m(i)c(2) (v(0)/c), where m(i)c(2) is the ion rest mass energy and v(0) is the shock upstream flow velocity. Furthermore, some of these suprathermal electrons may be effectively trapped for an infinitely long time when the Alfven Mach number M-A exceeds several tens, and they are accelerated up to the shock potential energy determined by the global shock size.