Date of Award

Summer 7-22-2014

Document Type

Thesis

Degree Name

Doctor of Philosophy (PhD)

Department

Aerospace Engineering Sciences

First Advisor

Xinlin Li

Second Advisor

Dan Baker

Third Advisor

Zoltan Sternovsky

Abstract

Earth's outer radiation belt is a highly dynamic region of the magnetosphere composed of relativistic electrons with often unpredictable variations in energy and spatial extent. Understanding this variable radiation environment is critical for protecting both spacecraft and humans in space. A number of competing acceleration and loss processes combine to produce net enhancements or depletions of the outer radiation belt. Electron precipitation into the atmosphere is a critical part of this loss, and quantified understanding of this mechanism is needed in order to understand and ultimately predict radiation belt dynamics. In the following work, we investigate the contribution of electron precipitation to radiation belt losses, looking at what times precipitation is important and at how much loss it contributes. Through a combination of long-term existing data sets as well as new CubeSat measurements we perform both statistical and detailed event studies to better understand the nature and extent of MeV electron loss to the atmosphere. We analyze measurements of precipitating electrons directly as well as electromagnetic waves that may be causing this precipitation. Our studies provide a more cohesive picture of outer radiation belt dynamics and the relationship between precipitating energetic electrons and global magnetospheric conditions.

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