火星壳磁场对电离层影响的综述

发布时间：2018-06-13 12:42

本文选题：火星探测 + 火星壳磁场　；参考：《中国科学:技术科学》2010年07期

【摘要】：火星壳磁场对电离层的影响是火星电离层研究的热点之一.本文总结了国际上针对火星壳磁场对电离层影响的研究.早期的火星电离层数据主要来自无线电掩星观测.根据无线电掩星观测结果,火星壳磁场主要影响电离层的电子密度标高和峰值电子密度.强水平磁场可以有效阻止等离子体的垂直扩散,导致顶部电离层电子密度的标高与光化平衡区域相近;而在类似极尖区的强垂直磁场区域,由于等离子体的垂直扩散增强,会导致扩散平衡区域电子密度标高的增加.MGS的无线电掩星观测发现在火星壳磁场比较强的南半球区域电离层主峰值电子密度平均略高于在北半球弱磁场区域的观测结果.MEX首次利用顶部探测雷达对火星电离层进行观测,其观测结果证实电离层主峰值电子密度的异常增加只发生在火星壳磁场中类似极尖区的开放磁场区域,而且峰值电子密度增加的幅度远大于无线电掩星观测的结果.造成在火星壳磁场类似极尖区的开放磁场区域出现电离层主峰值电子密度异常增加的可能机制有两种:一种与能量粒子的注入有关;而另一种与等离子体不稳定性的激发和波动加热有关.目前还无法确定是哪种机制起主要作用.在此基础上,本文提出了火星电离层和等离子体环境需要深入研究的几个问题.
[Abstract]:The influence of the magnetic field of the Martian crust on the ionosphere is one of the hotspots in the study of the ionosphere of Mars. This paper summarizes the international studies on the influence of the magnetic field of the Martian crust on the ionosphere. Early Mars ionospheric data came mainly from radio occultation observations. According to radio occultation observations, the magnetic field of the Martian crust mainly affects the electron density elevation and peak electron density in the ionosphere. The strong horizontal magnetic field can effectively prevent the vertical diffusion of the plasma, resulting in the elevation of the electron density of the ionosphere at the top is close to the photochemical equilibrium region, while in the strong vertical magnetic field region similar to the polar tip, the vertical diffusion of the plasma is enhanced. Radio occultation observations of MGS show that the main ionospheric peak electron density in the southern hemisphere with stronger magnetic field in the Martian crust is slightly higher on average than in the weak magnetic field region of the northern hemisphere. MEX used the top detection radar for the first time to observe the Martian ionosphere. The results show that the anomalous increase of the main peak electron density in the ionosphere occurs only in the open magnetic field region similar to the polar tip in the Martian shell magnetic field, and the amplitude of the increase in the peak electron density is much larger than that of the radio occultation observations. There are two possible mechanisms for the increase of the main ionospheric peak electron density in the open magnetic field region of the Martian shell magnetic field similar to the polar tip: one is related to the injection of energy particles; The other is related to the excitation and wave heating of plasma instability. It is not yet possible to determine which mechanism plays a major role. On this basis, several problems need to be studied in the ionosphere and plasma environment of Mars are presented.
【作者单位】：北京大学空间物理与应用技术研究所;
【基金】：国家自然科学基金项目(批准号:40704026,40774095) 北京市教委共建项目(批准号:XK100010404)资助
【分类号】：P185.3

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