[P-PS01] Outer Solar System Exploration Today, and Tomorrow

[PPS01-P03] Evolution of Icy Moon's Interior Uncovered by Laboratory Experiment: Modeling of Space Weather by Ion Irradiation

*Tomoki Kimura¹, Yusuke Nakauchi², Jun Kimura³, Koutaku Suzuki⁴, Yoshinori Nakata⁴, Toru Tamagawa⁵, Asami Hayato⁵, Toshio Nakano⁵, Go Murakami⁶, Kazuo Yoshioka⁷ (1.Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 2.Research Cluster for Space Science, Aizu University, 3.Graduate School of Science, Osaka University, 4.Wakasa-Wan Energy Research Center, 5.RIKEN Nishina Center for Accelerator-Based Science, 6.JAXA/ISAS, 7.Department of Complexity Science and Engineering, Tokyo University)

Keywords:Icy Bodies, Subsurface ocean, Plasma

In our solar system, several icy bodies have possibility for a liquid water ocean underneath a solid ice shell, while only Earth has ocean on the surface. The subsurface ocean could be potentially universal habitable environment. Duration of the subsurface ocean is an unsolved big problem for evolution of the icy body's interior and also for the possible life that has likely been evolving there. We uncover the evolutions of subsurface ocean based on the space weathering on solid surface that is driven by irradiation of energetic plasma around planets. Long-term space weathering at Ganymede that reaches Giga years is modeled by plasma irradiation to surface materials with laboratory beam experiment. Chronology for Ganymede's magnetic field excited by molten metallic core can be suggested based on a dependence of the space weathering on the Ganymede's magnetic field strength. We are going to pin down the subsurface ocean evolution from the magnetic field chronology. In this presentation, we report current status of our laboratory experiment made with an ion injector at Wakasa-wan Energy Research Center.