Title

Solar Wind-Magnetosphere Coupling and Global Energy Budgets in the Earth's Magnetosphere

Document Type

Dissertation

Publication Date

2000

Abstract

This thesis focuses on two different but related topics in magnetospheric physics: solar wind coupling into the magnetosphere and energy deposition within the magnetosphere. I first address solar wind coupling in a study of the interplanetary electric field and its influence on the high-altitude polar cap. I use POLAR EFI data and find changes in the electric field over the polar cap in response to sharp deviations in the interplanetary electric field. Then the focus is shifted towards estimation of global energy budgets. Estimates have been made in the past regarding the relative importance of auroral processes, ring current injection, Joule heating, and plasmoids, but have been limited due to a lack of available data. With the ISTP fleet of spacecraft, it is now possible to more quantitatively evaluate the amount of energy stored and released during magnetospheric substorms and storms. This study focuses on the ring current, which has often been assumed to be the largest energy sink during disturbed times. I use POLAR CAMMICE data to estimate the amount of energy deposited in the ring current for several storms. For these same storm intervals, I compare ring current energy estimates with estimates of Joule heating and auroral precipitation derived using AMIE results. What I find is a clear dominance of ionospheric energy deposition over other processes and a less significant contribution from the ring current.

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