The development of habitable conditions on Earth is tightly connected to the evolution of its atmosphere, which is strongly influenced by atmospheric escape. We investigate the evolution of the polar ion outflow from the open field line bundle, which is the dominant escape mechanism for the modern Earth. We perform Direct Simulation Monte Carlo (DSMC) simulations and estimate the upper limits on escape rates from the Earth's open field line bundle starting from 3 gigayears ago (Ga) to present assuming the present‐day composition of the atmosphere. We perform two additional simulations with lower mixing ratios of oxygen of 1% and 15% to account for the conditions shortly after the Great Oxydation Event (GOE). We estimate the maximum loss rates due to polar outflow 3 gigayears ago of 3.3×10²⁷ s⁻¹ and 2.4×10²⁷ s⁻¹ for oxygen and nitrogen, respectively. The total integrated mass loss equals to 39% and 10% of the modern atmosphere's mass, for oxygen and nitrogen, respectively. According to our results, the main factors that governed the polar outflow in the considered time period are the evolution of the XUV radiation of the Sun and the atmosphere's composition. The evolution of the Earth's magnetic field plays a less important role. We conclude that although the atmosphere with the present‐day composition can survive the escape due to polar outflow, a higher level of CO₂ between 3.0 and 2.0 Ga was likely necessary to reduce the escape.

中文翻译：

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从中亚流域到现在的地球极地流出的演变

地球上宜居环境的发展与大气的演化紧密相关，而大气的演化受到大气逸散的强烈影响。我们研究了从开放磁场线束流出的极性离子的演变过程，这是现代地球的主要逃逸机制。我们执行直接模拟蒙特卡洛（DSMC）模拟，并从3千兆年前（Ga）开始，假设当前的大气成分，估计从地球的开放野外线束逃逸率的上限。我们还进行了另外两个模拟，分别以1％和15％的较低氧气混合比说明了大氧化事件（GOE）之后不久的情况。我们估计3年前因极性外流而导致的最大损失率是3.3×10 ²⁷  s氧气和氮气分别为^-1和2.4×10 ²⁷  s ^-1。对于氧气和氮气，总的综合质量损失分别等于现代大气质量的39％和10％。根据我们的结果，在所考虑的时间段内控制极性流出的主要因素是太阳的XUV辐射的演变以及大气的成分。地球磁场的演变起着不重要的作用。我们得出的结论是，尽管由于极性流出，具有当今组成的大气能够幸免于逃逸，但为减少逃逸，可能有必要在3.0和2.0 Ga之间添加更高的CO ₂水平。