宇宙射线在行星及系外行星大气中的能量沉积
Energy deposition in planetary and exoplanetary atmospheres induced by cosmic rays
- University of Bern（伯尔尼大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究利用CosmicTransmutation代码模拟宇宙射线与行星磁场相互作用，发现磁场显著影响能量沉积，且需同时考虑银河宇宙射线和恒星高能粒子两种源。
AI中文摘要：
宇宙射线能够显著改变行星大气上层某些物种的丰度，尤其是在生物特征信号方面。为了全面理解这一影响的程度，精确模拟宇宙射线与行星磁场的相互作用至关重要。我们使用CosmicTransmutation代码研究了行星磁场对银河宇宙射线和恒星高能粒子通量的影响。我们发现，尽管由于两种粒子源的能量范围不同而导致效应有所差异，但两者都受到磁场的显著影响。对于无磁场的类地行星，恒星高能粒子的能量通量显著更高，但当磁场强度达到30微特斯拉（$\mu$T）或更高时，两种粒子源的能量通量变得相当。我们发现宇宙射线到达的大气压力显著低于先前使用更简单模型的研究结果，且大气成分对这一结果的影响较小。我们使用系外行星K2-18b的模型得到了类似的结果，尽管其半径显著大于地球。由于这两种宇宙射线源覆盖不同的能量范围，并因此受到磁场影响的方式不同，两种源都应被考虑。未来的研究应侧重于将宇宙射线与行星磁场相互作用的精确建模过程与大气化学模型相结合。这将需要通用环流模型来完整捕捉纬度和经度依赖性。
英文摘要：
Cosmic rays can significantly alter the abundances of certain species in the upper layers of planetary atmospheres, especially in terms of their biosignatures. To fully understand the extent of this effect, it is essential to accurately model the interactions of cosmic rays with planetary magnetic fields. We used the CosmicTransmutation code to study the effect of a planetary magnetic field on the flux of galactic cosmic rays and stellar energetic particles. We found that both particle sources are significantly affected by magnetic fields, even though the effects are different due to the varying energy ranges that characterize each source. The stellar energetic particle energy flux is significantly higher for an Earth-like planet with no magnetic field, but with a magnetic field of 30\,$μ$T or higher, the energy flux of the two sources becomes comparable. We find that the atmospheric pressures the cosmic rays reach are significantly lower than those found in previous studies using simpler models and that the effect of the atmospheric composition on this outcome is small. We found similar results using the model for the exoplanet K2-18b, even though the radius is significantly larger than Earth's. Because the two cosmic ray sources cover different energy ranges and are affected by the magnetic field in different ways as a result, both sources should be considered. Future studies should focus on combining an accurate modelling procedure of the interaction between cosmic rays and planetary magnetic fields with atmospheric chemistry models. This will require general circulation models to capture the latitudinal and longitudinal dependencies in full.
