Electron-Ion Coupling Upstream of Relativistic Collisionless Shocks
Electron-Ion Coupling Upstream of Relativistic Collisionless Shocks
复制标题
相对论无碰撞激波上游的电子-离子耦合
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
Y. Lyubarsky
中科院分区：
文献类型：
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作者：
Y. Lyubarsky
我们论证并通过格子粒子模拟证明，同步脉泽不稳定性可以在相对论磁化激波的前沿发展。这种不稳定性产生了强烈的低频电磁波，在激波的上游和下游传播。在激波的上游，这些波使电子滞后于离子，从而产生一个纵向电场，电子被加速到离子动能。然后，激波前沿的热化会产生具有相同温度的电子和离子的等离子体。在激波下游，脉泽产生的波的幅度可能超过激波压缩的背景磁场的强度。在这种情况下，激波加速的粒子通过非线性康普顿散射而不是通过同步加速器机制辐射。在低频段，辐射的光谱与同步辐射的光谱不同，这为模型提供了可能的观测测试。
We argue and demonstrate by particle-in-cell simulations that the synchrotron maser instability could develop at the front of a relativistic, magnetized shock. The instability generates strong low-frequency electromagnetic waves propagating both upstream and downstream of the shock. Upstream of the shock, these waves make electrons lag behind ions so that a longitudinal electric field arises and the electrons are accelerated up to the ion kinetic energy. Then thermalization at the shock front results in a plasma with equal temperatures of electrons and ions. Downstream of the shock, the amplitude of the maser-generated wave may exceed the strength of the shock-compressed background magnetic field. In this case the shock-accelerated particles radiate via nonlinear Compton scattering rather than via a synchrotron mechanism. The spectrum of the radiation differs, in the low-frequency band, from that of the synchrotron radiation, providing possible observational tests of the model.