Date of Award

3-10-2010

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Department of Engineering Physics

First Advisor

William F. Bailey, PhD.

Abstract

The purpose of this research was to improve modeling of midlatitude D-region ionospheric absorption of high frequency radio signals during solar X-ray flares through analysis of HF propagation data obtained during the HF Investigation of D-region Ionospheric Variation Experiment (HIDIVE) and obtained at the Canadian Space Agency NORSTAR riometer in Pinawa, Manitoba, Canada and X-ray flux data, as reported by GOES satellites. The findings of the data analysis were then used to validate and suggest improvements for two existing HF absorption models, the operational Space Weather Prediction Center (SWPC) D-region Absorption model and the physical AbbyNormal model. Analysis of the HIDIVE data revealed an absorption dependence on signal frequency and a dependence on solar zenith angle which differ from those used in the SWPC model. Analysis of nitric oxide (NO) density data obtained with the Student Nitric Oxide Explorer and during the Halogen Occultation Experiment provided improved methods of defining NO profiles within AbbyNormal.

AFIT Designator

AFIT-DS-ENP-09-J01

DTIC Accession Number

ADA516063

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