Abstract

This paper presents the results of calculating the efficiency of solar wind proton charge exchange as a function of variations in the column density of hydrogen atoms in the extended corona of Mars. The presence of regular density variations has been known for a long time and has been associated with the change of seasons on Mars. However, sporadic density variations in the upper Martian atmosphere were detected recently as well. They were caused by various processes in the underlying atmosphere, such as ejection of water vapor and ice particles at altitudes up to 100 km due to global dust storms, which was discovered in the Mars Express and MAVEN observations. Taking into account the variations in the column density with the observed amplitude up to one order of magnitude is absolutely necessary to correctly consider the interaction of solar wind protons with the Martian atmosphere. The calculations using the kinetic Monte Carlo model revealed that with a 2- and 5-fold increase in the column density of H atoms in the corona of Mars, the charge exchange efficiency also increases and reaches 6% and 8%, respectively, as compared to the base value of 4%. The energy spectrum of hydrogen atoms penetrating into the Martian atmosphere does not change and remains identical in structure to the spectrum of undisturbed solar wind protons. These estimates, combined with the previously developed kinetic model of the proton and hydrogen atom precipitation into the planetary atmosphere, make it possible to do the following: to trace all the stages of the penetration of the undisturbed solar wind protons into the dense layers of the atmosphere, as well as interpret the observed characteristics of proton auroras depending on the variations of atomic hydrogen content in the Martian corona.

中文翻译：

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火星扩展氢电晕变化对太阳风质子电荷交换效率的影响

摘要

本文介绍了计算太阳风质子电荷交换效率与火星扩展电晕中氢原子柱密度变化的函数关系的结果。长期以来，已知规则的密度变化已经存在，并且与火星的季节变化有关。但是，最近还发现了火星上层大气的零星密度变化。它们是由底层大气中的各种过程引起的，例如由于全球沙尘暴而在高达100 km的高度喷出水蒸气和冰粒，这是在“火星快车”和“ MAVEN”观测中发现的。要正确考虑太阳风质子与火星大气的相互作用，绝对有必要考虑到观测到的振幅高达一个数量级的柱密度变化。使用动力学蒙特卡洛模型进行的计算表明，随着火星电晕中H原子的列密度增加2倍和5倍，电荷交换效率也分别提高了，分别达到6％和8％。到4％的基准值。渗透到火星大气中的氢原子的能谱不会改变，并且在结构上与未受干扰的太阳风质子的光谱相同。这些估算值与先前开发的质子和氢原子沉淀到行星大气中的动力学模型相结合，