부산대학교 도서관

In this study, observations from the Jovian auroral distributions experiment, Jupiter energetic particle detector instrument, and Magnetic field investigation instruments on Juno are used to identify signatures of magnetic reconnection at Jupiter's dawn magnetopause and relate these signatures to the local plasma environment. Magnetopause crossings occurred between 73–114 Jovian radii and 4.3–6.2 magnetic local time at low latitudes. Reconnection signatures include plasma energization and ion velocity enhancements resembling reconnection jets. We test for diamagnetic suppression which considers the magnetic shear and plasma beta (β) before and after a magnetopause crossing. Findings show that a large majority of these dawn magnetopause crossings at Jupiter have a low likelihood for local magnetic reconnection (are diamagnetically suppressed) because of high delta β values and/or low magnetic shear angles across the magnetopause boundary. These crossings exhibit no evidence of local reconnection while crossings that are not diamagnetically suppressed show multiple signatures of reconnection, adhering to the Swisdak relation. Plain Language Summary: Magnetic reconnection is a process in which magnetic field lines merge and magnetic energy is transferred to the surrounding plasma. This causes plasma to be ejected at high speeds from the reconnection site. Magnetic reconnection at Jupiter's magnetopause is identified by observing signatures such as increased plasma velocities and energies as the spacecraft transitions from Jupiter's magnetic field to the interplanetary magnetic field or vice versa. Identifying these signatures using instruments aboard the Juno spacecraft helps to understand the physical processes at Jupiter's magnetopause. The draped magnetic field in the magnetosheath and Jupiter's magnetic field are similarly oriented for a significant number of the observed crossings and there is a significantly large difference in pressure across the magnetopause. As a result, local magnetic reconnection is suppressed for a majority of these magnetopause crossings and does not significantly contribute to the dynamics of solar wind interactions at Jupiter's dawn magnetopause during this time. Key Points: Sixty‐two magnetopause crossings at Jupiter's dawnside magnetosphere were identified and analyzed for signatures of magnetic reconnectionThirty‐nine percent of the crossings had magnetic shear angles less than 20°, resulting in a low probability for local reconnection at the magnetopauseCrossings with high (low) magnetic shear and low (high) Δβ are consistent with the Swisdak relation for reconnection probability [ABSTRACT FROM AUTHOR]