Solar Wind Interaction and Pressure Balance at the Dayside Ionopause of Mars
F. Chu, F. Duru, Z. Girazian, R. Ramstad, J. Halekas, D. A. Gurnett, D. D. Morgan, Xin Cao, A. J. Kopf
Due to the lower ionospheric thermal pressure and existence of the crustal magnetism at Mars, the Martian ionopause is expected to behave differently from the ionopause at Venus. We study the solar wind interaction and pressure balance at the ionopause of Mars using both in situ and remote sounding measurements from the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) instrument. We show that the magnetic pressure usually dominates the thermal pressure to hold off the solar wind in the ionopause at Mars, with only 13\% unmagnetized ionopauses observed over a 11-year period. We also find that the ionopause altitude decreases as the normal component of the solar wind dynamic pressure increases. Moreover, our results show that the ionopause thickness at Mars is mainly determined by the ion gyromotion and equivalent to about 5.7 ion gyroradii.
Subjects: Space Physics (physics.space-ph); Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2103.12785 [physics.space-ph] (or arXiv:2103.12785v1 [physics.space-ph] for this version)
Submission history
From: Feng Chu
[v1] Tue, 23 Mar 2021 18:32:09 UTC (1,934 KB)
