Electron Energetics in the Martian Ionosphere: Model Comparisons with MAVEN Data

Tuesday, 15 December 2015
Poster Hall (Moscone South)
Shotaro Sakai1, Ali Rahmati1, Thomas Cravens1, David L Mitchell2, Stephen W Bougher3, Christian Xavier Mazelle4, William K Peterson5, Francis Gerard Eparvier5, Juan M Fontenla6, Laila Andersson5 and Bruce Martin Jakosky7, (1)University of Kansas, Lawrence, KS, United States, (2)University of California Berkeley, Berkeley, CA, United States, (3)University of Michigan Ann Arbor, Ann Arbor, MI, United States, (4)University Paul Sabatier Toulouse III, Toulouse Cedex 09, France, (5)University of Colorado at Boulder, Boulder, CO, United States, (6)NorthWest Research Associates Boulder, Boulder, CO, United States, (7)University of Colorado at Boulder, Laboratory for Atmospheric and Space Physics, Boulder, CO, United States
A large part of the solar extreme ultraviolet and soft X-ray radiation absorbed in planetary upper atmospheres appears as photoelectrons and some of the energy ends up heating thermal electrons and increasing the electron temperature. Photoelectrons are important for the heating related to plasma temperatures, ionization and airglow production in planetary atmospheres. Measured electron fluxes provide insight into sources and sinks of energy in the Martian upper atmosphere. Suprathermal electron fluxes measured by the SWEA (Solar Wind Electron Analyzer) instrument onboard the MAVEN (Mars Atmosphere and Volatile EvolutioN) are providing insight into sources and sinks of energy in the Martian upper atmosphere. A two-stream electron transport code was used to interpret these observations including Auger electrons associated with K-shell ionization of carbon, oxygen and nitrogen. External electron fluxes from the Martian magnetosheath or tail, are also included. Electron and ion temperatures are found from numerical solutions of the energy equations and comparisons are made with the electron temperature measured by the MAVEN Langmuir Probe (e.g., Ergun et al., 2015). The overall implications of the plasma energetics for the Martian ionosphere will be discussed.