Date of Award

12-2018

Document Type

Thesis - Open Access

Degree Name

Master of Science in Electrical & Computer Engineering

Department

Electrical, Computer, Software, and Systems Engineering

Committee Chair

Dr. Edwin Mierkiewicz

First Committee Member

Dr. William Barott

Second Committee Member

Dr. Brian Butka

Abstract

The Investigating Near Space Interaction Regions (INSpIRe) observatory is an adapt- able research facility that is designed to use Fabry-Perot interferometer (FPI) to study the faint Balmer series emissions of the terrestrial upper thermosphere and exosphere, collectively known as the geocorona. This instrumentation is designed to be deployable to a clear-air site, necessitating remote operations of the entire observatory, including control and monitoring. The facility currently employs a siderostat to allow for pointing at sky targets, a pressure-tuned dual-etalon FPI to allow for high spectral resolution (R_80,000) measurements, and several charge-coupled device (CCD) imagers for guiding and collecting data. The environment is fully monitored using temperature, humidity, barometric pressure, and wind sensors. The INSpIRe observatory's primary purpose is to conduct a long timeline observing campaign that will contribute to three major areas of geocoronal research: geocoronal physics, structure/coupling, and variability.

After reviewing the theories and history of geocoronal research, an explanation of the observational methodology used in studying hydrogen via FPI is described. The systems design and remote operations software implementation is outlined. Significant progress has ensued since development began in 2014. The basic requirements of remote operations have been completed for a minimum of one FPI, including automatic logging, science data header population, and scripting capabilities. Full remote testing is currently incomplete. Strategies for future implementations and testing are included.

A case study is presented on an original model-data comparison of seasonal trends in Balmer-a emission intensity diurnal variation. This investigation serves as a demonstration of the scientific contributions that the INSpIRe observatory is capable of providing and shows, for the first, a seasonal trend in the evening-to-morning variation of H-a intensity. Observed diurnal asymmetry from a previously established dataset is found to be highest in the winter and lowest in the summer for the Northern hemisphere during solar maximum. Comparisons between modeled and observed diurnal intensity variation, generated using the Lyman Atmospheric Observations Radiative Transport (lyao_rt) code of Bishop [1] and employing the Mass Spectrometer and Incoherent Scatter model (MSIS) thermospheric hydrogen profiles, show good agreement near the equinoxes, but an overestimate of diurnal asymmetry in summer and a severe underestimate in winter. Overall, it is found that the model underestimates the absolute observed intensity by a factor of ~2. This work contributes to and agrees with the previous body of knowledge on geocoronal hydrogen; there is a limited amount of data for studying long timeline trends and the current models of atomic hydrogen do not accurately reflect the observations. Recommendations are provided for data collection with the INSpIRe observatory so as to best answer the current questions of geocoronal research.

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