On the evolution of the distribution of protons in the inner heliosheath
On the evolution of the distribution of protons in the inner heliosheath
复制标题
DOI：
10.1002/2016ja022561
复制
发表时间：
2016-09-01
影响因子：
2.8
通讯作者：
Scherer, Klaus
中科院分区：
文献类型：
--
作者：
Fahr, Hans-Joerg;Sylla, Adama;Scherer, Klaus
研究了太阳风质子分布函数沿日球层终止激波下游等离子体流的演化。从考虑对流变化、冷却、速度扩散、电荷交换注入和损失的等离子体流体标架中有效的动力学相空间输运方程出发，导出了由热太阳风和超热拾取质子组成的质子总数压力演化的相关矩方程。假定局部联合质子分布总是可以用一个所谓的分布来表示，得到了参数沿给定流线变化的常微分方程式。这样，就可以计算出整个内日鞘的质子速度分布。结果表明，速度扩散的加速效应有望过度补偿由于与冷的星际氢原子的电荷交换而对较高速度下质子分布的损失效应。虽然这证实了内侧(迎风)日鞘中的<；1.65的值，但同时它也揭示了早期研究中通常做出的常量假设应该被摒弃。
The evolution of the solar wind proton distribution function along the plasma flow downstream of the heliospheric termination shock is studied. Starting from a kinetic phase space transport equation valid in the bulk frame of the plasma flow that takes into account convective changes, cooling, velocity diffusion, and charge exchange-induced injection and loss, the associated moment equation for the evolution of the pressure of the total proton population consisting of thermal solar wind and suprathermal pickup protons is derived. Assuming that the local joint proton distribution can always be represented by a so-called distribution, an ordinary differential equation for the variation of the parameter along a given streamline is obtained. This way, the proton velocity distribution can be computed for the whole inner heliosheath. It is demonstrated that the accelerating effect of velocity diffusion is to be expected to overcompensate the loss effect on the proton distribution at higher velocities due to charge exchange with cold interstellar hydrogen atoms. While this corroborates a value of < 1.65 in the inner (upwind) heliosheath, at the same time it reveals that the assumption of a constant , which was commonly made in earlier studies, should be abandoned.