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

[PPS01-P03] Expected source regions of Jupiter’s hectometric radio components viewed from their polarization characteristics

*Hiroaki Misawa¹, Fuminori Tsuchiya¹, Atsushi Kumamoto², Yoshiya Kasahara³, Yoshizumi Miyoshi⁴, Masahiro Kitahara⁴, Satoko Nakamura⁴ (1.PPARC, Graduate School of Science, Tohoku University, 2.Department of Geophysics, Graduate School of Science, Tohoku University, 3.ARC-SAT, Kanazawa University, 4.ISEE, Nagoya University)

Keywords:Jupiter, hectometric radiation, polarization, source region

It has been known that Jupiter’s auroral radio emission in the hectometric wave range (HOM) is roughly classified into two type occurrence components. One is a component relating to solar wind variations (sw(solar wind)-HOM) appearing around CML (Central Melian system III Longitude of an observer) ~ 180deg when solar wind pressure enhances. The other one is generally more intense than sw-HOM and has no or weak relation with solar wind variations (nsw(non sw)-HOM) appearing around CML ~110deg and ~280deg (the 1^st and 2^nd nsw-HOM, respectively) when De (Jovicentric declination of an observer) ~ -1deg (Nakagawa et al., 2000; Nakagawa, 2003). Recently, we found one more nsw-HOM component appearing around CML ~340deg (the 3^rd nsw-HOM), which highly correlates occurrence of magnetic reconnection events in Jupiter’s magnetotail region (Misawa et al., 2018). This component is an important role for the studies of global magnetospheric dynamics of Jupiter since it is a possible remote marker of the reconnection events occurring in Jupiter’s magnetosphere. However, due to difficulty in precise direction finding in the hectometric wave range, the radio source of this component (and also those of the other components), that is, location of transported energy input should be originated from the tail region, has been still unrevealed.
In order to investigate source location of each HOM component we have made their polarization analyses using the data provided by High Frequency Analyzer (HFA) which is a subsystem of Plasma Wave Experiment (PWE) onboard the Arase (ERG) spacecraft. Preliminary analyses show that the 3^rd nsw-HOM is left-handed circular polarization. The result suggests that the 3^rd nsw-HOM is radiated from the southern hemisphere by taking account of Jupiter’s magnetic polarity. In the presentation, we will discuss possible sources of the 3^rd nsw-HOM based the polarization analyses by comparing the expected observable rays calculated from Jupiter’s magnetic field models, and will also show polarization characteristics and expected source regions of the other HOM components.