A survey of superthermal electron flux depressions, or “electron holes,” within the illuminated Martian induced magnetosphere
A survey of superthermal electron flux depressions, or “electron holes,” within the illuminated Martian induced magnetosphere
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对照亮的火星感应磁层内的超热电子通量凹陷或“电子空穴”的调查
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发表时间：
2016
期刊：
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通讯作者：
M. Fränz
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作者：
B. Hall;M. Lester;Jonathan D. Nichols;B. Sánchez–Cano;David Andrews;H. Opgenoorth;M. Fränz
由于火星缺乏一个全球性的内在磁场，太阳风直接与火星上层大气和电离层相互作用。局部强烈的残余地壳磁场的存在增加了这种相互作用，使火星等离子体系统成为太阳系内独特的环境。电子通量的快速减少，被称为“电子空穴”，发生在火星感应磁层（IM）内。我们提出了一个统计分析，这种现象确定从代理测量的电子通量的空间等离子体和高能中性原子电子光谱仪实验上的火星快车（MEX）航天器上的测量。这项研究于2004年2月9日至2014年5月9日期间完成。在本研究期间，在超过56%的MEX轨道中，在IM内观察到电子空穴，主要发生在低于1300 km的高度，大多数位于负X火星中心太阳轨道方向。火星表面以上的空间分布被观察到与Cain等人[ ]的磁场模型预测的地壳磁场非常相似，这表明它们在这些现象的形成中发挥了重要作用。
Since Mars lacks a global intrinsic magnetic field, the solar wind interacts directly with the Martian upper atmosphere and ionosphere. The presence of localized intense remnant crustal magnetic fields adds to this interaction, making the Martian plasma system a unique environment within the solar system. Rapid reductions in the electron flux, referred to as “electron holes,” occur within the Martian induced magnetosphere (IM). We present a statistical analysis of this phenomenon identified from proxy measurements of the electron flux derived from measurements by the Analyser of Space Plasmas and Energetic Neutral Atoms Electron Spectrometer experiment on board the Mars Express (MEX) spacecraft. The study is completed for the period of 9 February 2004 to 9 May 2014. Electron holes are observed within the IM in more than 56% of MEX orbits during this study period, occurring predominantly at altitudes less than 1300 km, with the majority in the negative X Mars‐Centric Solar Orbital direction. The spatial distribution above the surface of Mars is observed to bear close resemblance to that of the crustal magnetic fields as predicted by the Cain et al. [ ] magnetic field model, suggesting that they play an important role in the formation of these phenomena.