On the electron temperature downstream of the solar wind termination shock
On the electron temperature downstream of the solar wind termination shock
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关于太阳风终止激波下游的电子温度
DOI：
10.5194/angeo-31-1205-2013
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发表时间：
2013
影响因子：
1.9
通讯作者：
H. Fahr
中科院分区：
文献类型：
--
作者：
I. Chashei;H. Fahr
抽象的。本文研究了随太阳风对流到大太阳距离并最终通过太阳风终端激波的电子温度。除非在宇宙射线体系中的高能量下，否则从原位等离子体观测中对这些遥远电子的行为几乎一无所知。因此，人们默认这些电子，由于它们的绝热行为和消失的热传导或热膨胀过程，一旦它们最终到达太阳风终止激波（大约100 Au），就会迅速冷却到非常低的温度。在本文中，我们表明，这样的电子，但是，在他们的通道上的终端冲击由于冲击电场的行动进行过绝热加热，因此出现在下游侧作为一个大大加热等离子体物种。定量地观察这个加热过程，我们发现太阳风电子在终端激波下游达到2-4 × 106 K的温度，这取决于上游太阳风的整体速度和激波压缩比。因此，这些电子在构造这种冲击和确定下游等离子体流特性方面起着重要的动力学作用。此外，它们为进入的中性星际氢提供了额外的电离源，并激发X射线发射。它们的行为也类似于宇宙射线电子，并通过空间扩散延伸到0.1 Au量级激波上游的有限区域，从而也改变了上游太阳风的性质。
Abstract. In this paper we study the temperatures of electrons convected with the solar wind to large solar distances and finally transported over the solar wind termination shock. Nearly nothing, unless at high energies in the cosmic ray regime, is known about the thermodynamical behaviour of these distant electrons from in~situ plasma observations. Hence it is tacitly assumed these electrons, due to their adiabatic behaviour and vanishing heat conduction or energization processes, have rapidly cooled off to very low temperatures once they eventually arrive at the solar wind termination shock (at about 100 AU). In this paper we show that such electrons, however, at their passage over the termination shock due to the shock–electric field action undergo an over-adiabatic heating and therefore appear on the downstream side as a substantially heated plasma species. Looking quantitatively into this heating process we find that solar wind electrons achieve temperatures of the order of 2–4 × 106 K downstream of the termination shock, depending on the upstream solar wind bulk velocity and the shock compression ratio. Hence these electrons therewith play an important dynamical role in structuring this shock and determining the downstream plasma flow properties. Furthermore, they present an additional ionization source for incoming neutral interstellar hydrogen and excite X-ray emission. They also behave similar to cosmic ray electrons and extend to some limited region upstream of the shock of the order of 0.1 AU by spatial diffusion and thereby also modify the upstream solar wind properties.
IBEX 相关高能中性原子反映的日球层顶内 keV 高能离子群的光谱特性
影响因子：
6.5
作者：
Siewert;McComas;Schwadron
通讯作者：
Schwadron