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

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

*Kazushi Asamura¹, Manabu Shimoyama², Yoshifumi Futaana², Yoshifumi Saito¹, Yoshizumi Miyoshi³, Takeshi Sakanoi⁴, - PEP team (1.Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 2.Swedish Institute of Space Physics, 3.Nagoya University, 4.Tohoku University)

Keywords:JUICE spacecraft, PEP/JNA, Energetic neutral atoms

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.