Date of Award

Spring 1-1-2015

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Aerospace Engineering Sciences

First Advisor

Xinlin Li

Second Advisor

Delores Knipp

Third Advisor

Dan Baker

Fourth Advisor

Humberto Godinez

Fifth Advisor

Scott Palo

Abstract

Electrons in Earth's magnetosphere typically originate with energies below ten kiloelectron volts (keV). Electrons trapped in the radiation belts can have energies that exceed 10 MeV and must be naturally accelerated within Earth’s magnetosphere. Still, the processes that govern this highly dynamic region are not fully understood. The outer radiation belt is not only a scientific puzzle but understanding it is an operational necessity, as these high energy electrons are capable of damaging spacecraft and can even result in spacecraft failure. In this work, we investigate our ability to observe these particles and understand the natural acceleration processes that generate them. We approach the problem on three fronts: (i) from an instrumentation perspective we develop a first-of-its- kind miniaturized particle telescope flown on a CubeSat platform, (ii) from an observational perspective we investigate in detail an outer belt enhancement case-study, and (iii) from a modeling perspective we develop a data assimilation model to better understand the mechanisms causing the acceleration. Finally, we construct an event-specific method to estimate electron lifetimes for diffusion models using CubeSat data, and use it to fully investigate the case study using the assimilative model, ultimately combining the three approaches. The ensuing results substantiate CubeSats as scientific observatories, demonstrate new data assimilation applications to the radiation belts, and strengthen our understanding of magnetospheric dynamics and the role of acceleration mechanisms.