Pristine Solar Wind Deep in the Collisional Atmosphere of Mars
- 1Department of Physics and Astronomy, University of Iowa, Iowa City, USA
- 2Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia, USA
At Mars, the solar wind is usually decelerated and heated at the bow shock, then diverted around the planet by the induced magnetosphere. Recently, however, Crismani et. al. (2019) presented MAVEN (Mars Atmosphere and Volatile EvolutioN) observations of an interesting event, where near-pristine solar wind was observed in the collisional atmosphere below 200 km. We searched through seven years of MAVEN SWIA (Solar Wind Ion Analyzer) observations to determine how often these types of events occur. We found at least 15 orbits during which near-pristine solar wind was observed below 200 km. In this presentation, we will discuss the occurrence rate of the events and characterize the planetary and solar wind conditions under which they are observed. Finally, we will discuss the implications of solar wind having direct access to the collisional atmosphere, which may include localized (1) ionization that alters the structure of the ionosphere, (2) heating of the thermosphere, (3) energization of ions to escape speeds, and (4) patchy proton aurora.
Reference: Crismani, M. M. J., Deighan, J., Schneider, N. M., Plane, J. M. C., Withers, P., Halekas, J., et al. (2019). Localized ionization hypothesis for transient ionospheric layers. Journal of Geophysical Research: Space Physics, 124, 4870–4880. https://doi.org/ 10.1029/2018JA026251
How to cite: Girazian, Z., Halekas, J., Ruhunusiri, S., and Fowler, C.: Pristine Solar Wind Deep in the Collisional Atmosphere of Mars, Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-739, https://doi.org/10.5194/epsc2022-739, 2022.
