Type of Document	Dissertation
Author	Wilder, Frederick Durand
URN	etd-04012011-110034
Title	The Non-Linear Electrodynamic Coupling Between the Solar Wind, Magnetosphere and Ionosphere
Degree	PhD
Department	Electrical and Computer Engineering
Advisory Committee	Advisor Name Title Clauer, C. Robert Committee Chair Baker, Joseph B. H. Committee Member Pratt, Timothy J. Committee Member Ruohoniemi, J. Michael Committee Member Scales, Wayne A. Committee Member Simonetti, John H. Committee Member
Keywords	Solar Wind Ionosphere Magnetosphere Electromagnetics Plasma Physics
Date of Defense	2011-03-29
Availability	unrestricted
Abstract The polar electric potential imposed on the ionosphere by coupling between the earth’s magnetosphere and the solar wind has been shown to have a non-linear response to the interplanetary electric field (IEF). This dissertation presents an empirical study of this polar cap potential saturation phenomenon. First, the saturation of the reverse convection potential under northward is demonstrated using bin-averaged SuperDARN data. Then, the saturation reverse convection potential is shown to saturate at a higher value at higher solar wind plasma beta. The reverse convection flow velocity is then compared with cross-polar cap flows under southward IMF under summer, winter and equinox conditions. It is demonstrated that the reverse convection flow exhibits the opposite seasonal behavior to cross polar cap flow under southward IMF. Then, an interhemispheric case study is performed to provide an explanation for the seasonal behavior of the reverse convection potential. It is found using DMSP particle precipitation data that the reverse convection cells in the winter circulate at least partially on closed field lines. Finally, SuperDARN and DMSP data are merged to provide polar cap potential measurements for a statistical study of polar cap potential saturation under southward IMF. It is found that the extent of polar cap potential saturation increases with increasing Alfvenic Mach number, and has no significant relation to Alfven wing transmission coefficient or solar wind dynamic pressure.
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