Japan Geoscience Union Meeting 2023

Presentation information

[E] Online Poster

P (Space and Planetary Sciences ) » P-PS Planetary Sciences

[P-PS05] Mars and martian moons

Tue. May 23, 2023 3:30 PM - 5:00 PM Online Poster Zoom Room (1) (Online Poster)

convener:Hideaki Miyamoto(University of Tokyo), Takeshi Imamura(Graduate School of Frontier Sciences, The University of Tokyo), Tomoki Nakamura(Department of Earth and Planetary Materials Sciences, Faculty of Science, Tohoku University), Hidenori Genda(Earth-Life Science Institute, Tokyo Institute of Technology)

On-site poster schedule(2023/5/23 17:15-18:45)

3:30 PM - 5:00 PM

[PPS05-P13] A technique of retrieving the exospheric number density distribution from pickup ion ring distributions observed by MAVEN/STATIC and its application to future MMX/MSA observations

*Kei Masunaga1, Naoki Terada2, Francois Leblanc3, Shotaro Sakai2, Shoichiro Yokota4, Yuki Harada5, Takuya Hara6, Kanako Seki7, Atsushi Yamazaki1, Tomohiro Usui1 (1.Japan Aerospace Exploration Agency, 2.Department of Geophysics, Graduate School of Science, Tohoku University, 3.LATMOS, Sorbonne Universite, 4.Graduate School of Science, Osaka University, 5.Graduate School of Science, Kyoto University, Kyoto, Japan, 6.University of California Berkeley, 7.Department of Earth and Planetary Science, Graduate School of Science, University of Tokyo)

Keywords:Mars, pickup ions, exosphere, MAVEN, MMX

Ion pickup by the solar wind is ubiquitous in space plasma, generating pickup ions. Because pickup ions are originally produced by ionization of the exospheric neutral atmosphere, their measurements contain information on the exospheric neutral abundance. Here we establish a method to retrieve exospheric number densities, by analyzing ion velocity distribution functions of pickup ions measured by the Mars Atmosphere and Volatile EvolutioN spacecraft. We retrieved exospheric oxygen density distribution between altitudes of ~1,000 km and 10,000 km around Mars. The consistency between the retrieved oxygen density distribution the modeled density distribution of the Exospheric General Model suggests that the oxygen atoms are mainly produced by dissociative recombination of O2+ in the Martian ionosphere. This method may be applied to other space missions to study the upper atmosphere of planets, moons, and small bodies in the solar system, where pickup ions exist. In this presentation, we discuss the application of this method to our future observations of the Mass Spectrum Analyzer on the Martian Moons eXploration spacecraft.