Solar Wind-Magnetospheric Coupling and its Relationship with the Aurora in the Polar Regions of Jupiter

Joyce, Hannah and Ray, Licia (2026) Solar Wind-Magnetospheric Coupling and its Relationship with the Aurora in the Polar Regions of Jupiter. PhD thesis, Lancaster University.

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Abstract

The overarching aim of this research is to explore how solar wind–magnetosphere coupling influences Jupiter's polar aurora. In particular, the investigation focuses on whether magnetic reconnection, as a large-scale interaction, accounts for observed variations in auroral emissions at high latitudes. Additional consideration is given to energy transfer via vortices generated by the Kelvin-Helmholtz (K-H) instability, as well as the influence of solar wind dynamic pressure and interplanetary magnetic field (IMF) strength on auroral behaviour. The central question addressed in this thesis is whether emissions in the swirl, noon active and the dusk active regions are driven by solar wind interactions with the magnetosphere or result primarily from Jupiter’s internal dynamics, as is the case for the main auroral emission. To address this question, the study is structured around two complementary chapters. The first examines the statistical relationship between solar wind parameters and auroral brightness. The second evaluates reconnection voltage and energy transfer associated with the K-H instability. It is found that the swirl and noon active regions show no correlation with any solar wind parameters, while the dusk active region shows a moderate correlation with solar wind dynamic pressure, magnetic field strength and Kelvin-Helmholtz instabilities formed on the dawn flank. The motivation for this research arises from the unresolved nature of Jupiter’s polar aurora. The driving mechanisms for the emissions in all three polar regions remain poorly understood. Although multiple theories propose different magnetic topologies and spectral characteristics, no consensus has been established. Assessing the influence of the solar wind contributes to the broader effort to characterise the processes responsible for Jupiter’s polar auroral features.