Date of Award

Spring 2011

Project Type

Thesis

Program or Major

Physics

Degree Name

Master of Science

First Advisor

Charles J Farrugia

Abstract

A key parameter in determining the flow of the solar wind around the magnetosphere is the Alfven Mach number (Ma) because it determines conditions at the bow shock. High Ma approaches the gas dynamic limit of flow around the magnetosphere, while low Ma implies strong magnetic forces on the flow. We study a long interval of high Ma during the recent pronounced solar minimum 2007--2009, and derive the magnetopause and bow shock shapes from data. We compare our results with models of the magnetopause and properties of the bow shock and find that during this period, the subsolar magnetosheath was 1 Re thinner and the magnetopause is more flared than other models predict. For low Ma, we study Interplanetary Coronal Mass Ejections (ICME) during their northward phase, and present five examples of 34 observed ion accelerations, observed by Geotail and Cluster, in the magnetosheath clue to draping of the IMF around the magnetosphere. Comparing with recent theory, we find good agreement as we investigate their (1) Ma dependence, and (2) their location relative to the east-west terminator.

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