Solar wind interaction with Mars: electric field morphology and source terms

Abstract

The correlation between space environment conditions and the properties of escaping ions is a central topic of Mars research. Although empirical correlations have been visible in the data, a physics-based interpretation, rather than statistics-based pictures, has not been established yet. As a first effort, we investigate the electric field, the direct contributor to ion acceleration, in the Mars plasma environment from a hybrid plasma model (particle ions and fluid electrons). We use Amitis, a hybrid model combined with an observation-based ionospheric model, to simulate the Mars-solar wind interaction under nominal solar wind plasma conditions for perpendicular and Parker spiral directions of the interplanetary magnetic field (IMF). The simulations show 1) The electric field morphology is structured by the IMF direction and the different plasma domains in the solar wind-Mars interaction. 2) Asymmetry of the electric field between the hemispheres where the convective electric field points inward and outward, respectively, due to the mass loading and asymmetric draping of the magnetic field lines. 3) The motional electric field dominates in most regions, especially in the dayside magnetosheath. 4) The Hall term is an order of magnitude weaker and significant in the magnetotail and plasma boundaries for a perpendicular IMF case. The Hall term is relatively stronger for the Parker spiral case. 5) The ambipolar electric field, in principle, agrees with MAVEN measurements in the magnetosheath.

Detection of magnetospheric ion drift patterns at Mars

“…Consequently, the magnitude of the electric field ( ) that contributes to the radial component of should be lower than 0.05 mV/m. Thus, the total magnitude of electric fields should be on the order of 0.1 mV/m, consistent with the latest simulation of the convective electric fields at Mars (0.1-1 mV/m) 49 . This value significantly exceeds the corotation electric field (0.01 mV/m) at this altitude (around 600 km), indicating that the potential existence of convective or impulsive electric fields.…”

Unveiling the 3D Structure of Magnetosheath Jets

“…Amitis has been extensively applied to study plasma interactions with various planetary bodies including the Moon, Mercury, Ganymede, Mars, Comets, and several asteroids (e.g., Fatemi et al, 2017;Fuqua-Haviland et al, 2019;Fatemi et al, 2020;Aizawa et al, 2021;Poppe et al, 2021;Rasca et al, 2022;Fatemi et al, 2022;Shi et al, 2022;X.-D. Wang et al, 2023;Poppe & Fatemi, 2023;Gunell et al, 2024). In addition, its results have been successfully validated through comparison with spacecraft observations (e.g., Fatemi et al, 2017Fatemi et al, , 2020Aizawa et al, 2021;Rasca et al, 2022;Fatemi et al, 2022;X.-D. Wang et al, 2023), theories (Fuqua-Haviland et al, 2019), and other kinetic and magnetohydrodynamic (MHD) models (Fatemi et al, 2017;Aizawa et al, 2021).…”

Characterizing the current systems in the Martian ionosphere

“…This discrepancy suggests that the asymmetry is more likely a feature of ionospheric currents rather than being a consequence of magnetospheric currents. Note that the most recent MHD or hybrid simulation results of Martian current system fail to replicate the ionospheric current systems 47,48,49 . This limitation likely arises because these simulations lack an ionospheric dynamo.…”