Solar Wind Interactions at Jupiter's Dawn Magnetopause: A Study of Magnetic Reconnection and Kelvin-Helmholtz Instabilities

Date

2024

Authors

Montgomery, Jake

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Abstract

The primary objective of this dissertation is to understand the significance of solar wind interactions at Jupiter's dawn magnetopause through the analysis of JADE, JEDI, and MAG observations on Juno. The observations of in situ plasma and magnetic field observations span from 73 – 114 RJ and 4.3 – 6.2 hrs local time at latitudes ≤ |20˚|. The same survey of 62 magnetopause crossings is used for all three studies to retain consistency throughout this dissertation. In our first study, each magnetopause crossing is analyzed for up to three signatures of magnetic reconnection using ion and electron energy spectrograms and ion moments and is plotted on a Swisdak relation plot. The results from this study conclude that many magnetopause crossings contain magnetic shear angles less than 20˚ and high |∆β| values and are therefore locally diamagnetically suppressed. However, 24% of the magnetopause crossings show strong evidence for local magnetic reconnection and this solar wind interaction type is an impactful driver of plasma transport at Jupiter due to the reorientation of field lines and plasma jets traveling away from the reconnection site. For our second study, the Kelvin-Helmholtz Instability (KHI) condition is applied to the same 62 magnetopause crossings using thermal ion densities and velocities along with ambient magnetic field observations. Key results from this study include the first observational evidence for KHIs at Jupiter and 40% of magnetopause crossings satisfy the KHI condition. Our final study utilizes in situ observations of the thermal plasma and magnetic field to characterize Jupiter's boundary layer. Results from this study show that plasma is transported across the magnetopause in both directions, the primary characteristic of Jupiter's boundary layer is a dual distribution of magnetosphere and magnetosheath electrons, and ion flow speeds are opposite the direction of corotation on the dawnside.

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Keywords

Jupiter, Kelvin-Helmholtz, Magnetic Reconnection, Magnetosphere, Plasma

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Department

Physics and Astronomy