Ionospheric escape from Mars is an important process for the erosion of the Martian atmosphere. The heavy ion outflow is dominated by and O⁺, however, the Martian ionosphere consists of many more ion species. In the dayside ionosphere below roughly 220 km altitude, is the second most dominant ion, and higher up and in the nightside ionosphere other ions species with a mass near but below that of (28–30 Atomic Mass Unit [AMU], e.g., CO⁺, , HCO⁺, NO⁺, etc.) gain in importance. However, their contribution to the ionospheric outflow is often obscured by the dominant ions and O⁺. Therefore, we perform a peak fitting to the mass spectrum of SupraThermal and Thermal Ion Composition onboard Mars Atmosphere and Volatile EvolutioN. This method is validated against the mass spectrum given by Neutral Gas and Ion Mass Spectrometer, and results in the ionosphere agree qualitatively very well. A statistical study is then performed to study the low‐energy (<100 eV) heavy ion outflow. We find that can be seen throughout the Martian magnetosphere, but it escapes only in small amounts at a mean rate of less than 1% of the rate. On the other hand, we find that the ions with a mass from 28 to 30 AMU, which were previously unknown in the Martian ion escape, are an important part of the ionospheric outflow, with a mean escape rate that reaches 32% of the rate.

中文翻译：

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从火星电离层逃逸及其他重次离子

来自火星的电离层逃逸是侵蚀火星大气的重要过程。大量的离子流出主要受O ⁺和O ^+的控制，但火星电离层由更多的离子组成。在大约220 km高度以下的白天电离层中，是第二大主导离子，在更高的位置；在夜晚电离层中，其他离子的质量接近但低于（28-30原子质量单位[AMU]），例如CO ⁺，，HCO ⁺，NO ⁺等）变得越来越重要。但是，它们对电离层流出的贡献通常被主要离子和O ⁺掩盖。。因此，我们对火星大气和挥发性挥发物上的超热和热离子组成的质谱图进行了峰拟合。该方法针对中性气体和离子质谱仪给出的质谱图进行了验证，结果表明电离层的定性非常好。然后进行统计研究以研究低能（<100 eV）重离子流出。我们发现，在整个火星磁层中都可以看到这种现象，但是它仅以少量的逸散率以不到速率的1％逸出。另一方面，我们发现质量为28至30 AMU的离子是火星离子逸出之前未知的，是电离层流出的重要组成部分，平均逸出率达到该速率的32％。