Force Analysis of Venus’s Induced Magnetosphere: A Multifluid Hall-Magnetohydrodynamics Study

Understanding which processes control atmospheric escape and the loss of water from planetary environments is crucial. The ESA’s Venus Express spacecraft has observed a significant depletion in Venus’s upper atmosphere, driven by the solar wind. In such scenarios, the electromagnetic force can accelerate planetary ions to energies that allow them to escape from the planet. However, it is extremely challenging to directly measure electromagnetic forces on planetary ions. Here we present a 3D multifluid Hall-magnetohydrodynamics simulation model to investigate electromagnetic force terms and the effects of each term on solar wind plasma and planetary ions. We find that the total electromagnetic force reaches its peak near the bow shock and the magnetic pileup boundary, with obvious asymmetric characteristics, which slows down the solar wind plasma and compresses the heavy ions toward Venus. In addition, the morphology of the convection electric field force shows obvious north-south asymmetry, which leads to the formation of asymmetric structures and plasma flows in the Venusian magnetotail. The electromagnetic force patterns obtained by simulation are consistent with the results and speculation from observations, suggesting that the multifluid model developed here has substantial capacity in further analysis regarding planetary ion escape.