Supermagnetosonic Jets behind a Collisionless Quasiparallel Shock
Supermagnetosonic Jets behind a Collisionless Quasiparallel Shock
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DOI：
10.1103/physrevlett.103.245001
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发表时间：
2009-12-11
影响因子：
8.6
通讯作者：
Reme, H.
中科院分区：
文献类型：
--
作者：
Hietala, H.;Laitinen, T. V.;Reme, H.
无碰撞准平行激波的下游区域的结构包含具有高动能密度的体流，来自先前未识别的源。我们目前的集群多航天器测量这种类型的supermagnetosonic射流以及一个弱的二次激波前鞘内，使我们能够提出以下生成机制的射流：准平行冲击固有的局部曲率变化可以创建快速，偏转射流伴随着下游区域的密度变化。如果射流的速度在障碍物的参考系中是超（磁）音速的，则在更靠近障碍物的护套中形成第二冲击波阵面。我们的结果可以应用于许多等离子体环境中的无碰撞准平行激波。
The downstream region of a collisionless quasiparallel shock is structured containing bulk flows with high kinetic energy density from a previously unidentified source. We present Cluster multispacecraft measurements of this type of supermagnetosonic jet as well as of a weak secondary shock front within the sheath, that allow us to propose the following generation mechanism for the jets: The local curvature variations inherent to quasiparallel shocks can create fast, deflected jets accompanied by density variations in the downstream region. If the speed of the jet is super(magneto)sonic in the reference frame of the obstacle, a second shock front forms in the sheath closer to the obstacle. Our results can be applied to collisionless quasiparallel shocks in many plasma environments.