1. On Energization and Loss of the Ionized Heavy Atom and Molecule in Mars' Atmosphere
- Author
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Zhao, J. -T., Zong, Q. -G., Liu, Z. -Y., Zhou, X. -Z., Wang, S., Ip, W. -H., Yue, C., Li, J. -H., Hao, Y. -X., Rankin, R., Degeling, A., Fu, S. -Y., Zou, H., and Wang, Y. -F.
- Subjects
Physics - Space Physics ,Astrophysics - Earth and Planetary Astrophysics - Abstract
The absence of global magnetic fields is often cited to explain why Mars lacks a dense atmosphere. This line of thought is based on a prevailing theory that magnetic fields can shield the atmosphere from solar wind erosion. However, we present observations here to demonstrate a counterintuitive understanding: unlike the global intrinsic magnetic field, the remnant crustal magnetic fields can enhance atmosphere loss when considering loss induced by plasma wave-particle interactions. An analysis of MAVEN data, combined with observation-based simulations, reveals that the bulk of O+ ions would be in resonance with ultra-low frequency (ULF) waves when the latter were present. This interaction then results in significant particle energization, thus enhancing ion escaping. A more detailed analysis attributes the occurrence of the resonance to the presence of Mars' crustal magnetic fields, which cause the majority of nearby ions to gyrate at a frequency matching the resonant condition ({\omega}-k_{\parallel} v_{\parallel}={\Omega}_i) of the waves. The ULF waves, fundamental drivers of this entire process, are excited and propelled by the upstream solar wind. Consequently, our findings offer a plausible explanation for the mysterious changes in Mars' climate, suggesting that the ancient solar wind imparted substantially more energy., Comment: 16 pages & 5 figures & Supplementary Material
- Published
- 2024