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

[PPS01-04] Low-energy energetic neutral atom analyzer (PEP/JNA) onboard the JUICE mission

*浅村 和史¹、下山 学²、二穴 喜文²、斎藤 義文¹、三好 由純³、坂野井 健⁴、PEP team - (1.宇宙航空研究開発機構、2.Swedish Institute of Space Physics、3.名古屋大学宇宙地球環境研究所、4.東北大学)

キーワード：JUICE 衛星、PEP/JNA、非熱的中性粒子観測

We have developed a low-energy (10eV-3keV) energetic neutral atom analyzer (PEP/JNA), which is onboard the JUICE spacecraft. The spacecraft is to be launched this April. After arrival at the Jupiter system, the spacecraft will orbit around Jupiter, make fly-bys of Europa, Ganymede, and Callisto, and finally orbit around Ganymede. Ganymede has its own intrinsic magnetic field. Because of this, a magnetosphere is considered to be formed around Ganymede due to interactions between plasmas in the Jovian magnetosphere and Ganmede's magnetic field. However, its characteristics are different from the terrestrial ones, since Alfven Mach number of upstream plasma flow (corotational plasma flow around Jupiter) is less than 1 (sub-sonic). PEP/JNA will reveal characteristics of the Ganymede's magnetosphere by measurement of scattered and sputtered particles generated by the precipitation of plasma particles onto the Ganymede's surface. Measurement of these particles will provide the spatial distribution of plasmas remotely, since electric/magnetic fields do not affect the trajectories of neutral particles. We will discuss the status and characteristics of the PEP/JNA flight model, and its observational targets.