Ultra‐low Frequency Foreshock Waves and Ion Dynamics at Mars

Abstract

We study the solar wind interaction with Mars in a global three‐dimensional hybrid model. A well‐developed, vast ion foreshock forms under a strongly flow‐aligned interplanetary magnetic field (IMF) configuration but otherwise nominal solar wind and solar minimum photon flux conditions. Large‐scale ultra‐low frequency (ULF) waves are excited in the foreshock by backstreaming ions. The foreshock ULF waves constitute two distinct regions in the analyzed solar wind and IMF situation: the near region where the wave period is 71–83 s and the far region where the wave period is 25–28 s. The near foreshock region waves transmit downstream through the bow shock and affect dynamics of the solar wind and planetary ion populations. Especially, ion precipitation rate into the exobase and planetary ion escape rates fluctuate at the ULF wave period corresponding to the near foreshock region. The peak‐to‐peak amplitude of the modulation is few percent or less. Interestingly, ionospheric oxygen ion escape fluxes show more than two orders of magnitude local modulations in the heavy plume at the same period. Finally, the escape rates of the ionospheric oxygen ion populations are enhanced by 60–70% under flow‐aligned IMF compared to nominal upstream conditions.

Kelvin–Helmholtz Instability at Mars: In Situ Observations and Kinetic Simulations

“…In particular, recent research by Fowler et al (2022) has shown that during radial and quasi-radial IMF conditions at Mars, the near-space environment becomes highly dynamic and disturbed compared to more typical conditions. Jarvinen et al (2022) have also demonstrated that wave excitation and ion escape rate depend on the location of crustal anomalies, using a global three-dimensional hybrid model. To further understand the impact of these factors, we conducted two additional simulation cases.…”

“…Martian ions are generated via photoionization of hydrogen and oxygen in the exosphere coronae and oxygen ion emission from the ionosphere. The production rates and profiles of planetary ions are the same as in Jarvinen et al (2022). The IMF is set to 3 nT along the y-direction, causing the solar wind electric field to point in the z-direction.…”

Deformations at Earth’s dayside magnetopause during quasi-radial IMF conditions: Global kinetic simulations and Soft X-ray Imaging

“…In this paper, the interaction of the solar wind with Earth's magnetosphere has been simulated by the three-dimensional (3-D) global hybrid simulation platform RHybrid (e.g., Jarvinen et al 2018Jarvinen et al , 2020Jarvinen et al , 2022Kallio et al 2022). The model setup includes the undisturbed, upstream solar wind ions injected in the simulation from the front ( ) wall along the direction with a drifting Maxwellian velocity distribution.…”

Solar Orbiter Data‐Model Comparison in Venus' Induced Magnetotail

“…In addition to the SolO observations, the results of the global hybrid simulation RHybrid, described in Jarvinen et al (2018), are utilized as a means to further investigating the structure of the magnetotail of Venus and the Venus-solar wind interaction through the comparison with the real data. The model setup is similar to earlier studies (Jarvinen et al, 2020(Jarvinen et al, , 2022) except here we use a larger simulation domain than before to allow the analysis of the far Venus tail. The Lorentz force determines the motion of solar wind and planetary ions, which are treated as macroscopic particle clouds (macroparticles), while electrons are modeled as a charge-neutralizing and massless adiabatic fluid (Jarvinen et al, 2020).…”