The Mediation of Collisionless Oblique Magnetized Shocks by Energetic Particles
The Mediation of Collisionless Oblique Magnetized Shocks by Energetic Particles
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DOI：
10.3847/1538-4357/aaeb91
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发表时间：
2018-11
期刊：
影响因子：
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通讯作者：
P. Mostafavi;G. Zank;G. Webb
中科院分区：
文献类型：
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作者：
P. Mostafavi;G. Zank;G. Webb
许多航天器的观测表明，许多日光层激波的存在显着影响的高能粒子，如太阳高能粒子，拾取离子（PUI），和异常宇宙射线。例如，新地平线号航天器最近的观测表明，PUI压力大于太阳风中的热太阳风压力。旅行者2号对日球层终止激波（HTS）的观测表明，它完全由超热质子能量介导，HTS处的耗散过程不是由于热太阳风质子，而是由于质子能量介导。我们引入了一个等离子体模型来研究由超热高能粒子介导的无碰撞斜磁化冲击波的结构。结果表明，在除θ = 54 °外的所有角度，无碰撞热流和高能粒子粘性的结合都能完全确定无碰撞斜激波的结构。这个角度的限制是技术性的，部分来自假设的粘性系数的简化形式。在模拟的高温超导，我们表明，PUI被加热远超过热气体通过高温超导过渡，因此高温超导介导的PUI。我们研究了不同的值的高温超导体的结晶度，并发现，一个平行的高温超导体加热PUI更多的背景热气体相比，它在一个垂直的高温超导体。
Numerous spacecraft observations reveal that many heliospheric shocks are significantly affected by the presence of energetic particles such as solar energetic particles, pickup ions (PUIs), and anomalous cosmic rays. Examples include recent observations by the New Horizon spacecraft that show that the PUI pressure is larger than the thermal solar wind pressure in the solar wind. Voyager 2 observations of the heliospheric termination shock (HTS) show that it is completely mediated by suprathermal PUIs, and that the dissipation process at the HTS is not due to the thermal solar wind protons but to PUIs. We introduce a plasma model to study the structure of collisionless oblique magnetized shocks mediated by suprathermal energetic particles. We show that the incorporation of both collisionless heat flux and viscosity associated with energetic particles can completely determine the structure of collisionless oblique shocks for all angles except θ = 54.°7. The limitation at this angle is technical and comes in part from the assumed simplified form of the viscosity coefficient. In modeling the HTS, we show that PUIs are heated much more than the thermal gas through the HTS transition, and thus the HTS is mediated by PUIs. We study different values of the HTS obliquity and find that a parallel HTS heats PUIs more compared to the background thermal gas than it does at a perpendicular HTS.