Observation of a `Cosmic-Ray-Modified' Interplanetary Shock
Observation of a `Cosmic-Ray-Modified' Interplanetary Shock
复制标题
“宇宙射线修正”行星际激波的观测
DOI：
10.1029/2004ja010941
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发表时间：
1999
影响因子：
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通讯作者：
T. Terasawa
中科院分区：
文献类型：
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作者：
T. Terasawa
我们发现1994年2月21日的行星际激波具有宇宙线修正激波(CRMS)的特征，其中等离子体流的减速约50公里/S(在激波静止标架中看到)发生在激波本身到达之前，这可以用高能电子(~40keV)和质子(50keV-4 MeV)携带的‘宇宙线’压力的增加来解释。进一步观察到上游太阳风的质量通量和冲压具有很大的时间变化，我们认为这是由于伴随CRMS的Drury的声学不稳定所致。据作者所知，这是这种不稳定性的第一个观测证据，据信这种不稳定性在各种天体物理环境中发挥着重要作用。
We show that a propagating interplanetary shock on 21 Feb 1994 had the feature of a cosmic-ray-modified shock (CRMS), where the deceleration of the plasma flow by ~50 km/s (seen in the shock rest frame) occurred before the arrival of the shock itself and is explicable in terms of the increase of the 'cosmic-ray' pressures carried by energetic electrons (~ 40 keV) and protons (50 keV - 4 MeV). It is further observed that the mass flux and ram pressure of the upstream solar wind showed large time variations, which we concluded to be attributable to the Drury's acoustic instability accompanying with the CRMS. To the authors' knowledge, this is the first observational evidence of this instability, which is believed to play important roles in various astrophysical environments.