Date of Award

Summer 6-2008

Document Type

Thesis - Open Access

Degree Name

Master of Science in Space Science

Department

Physical Sciences

Committee Chair

John M. Hughes

Committee Member

G. G. Sivjee

Committee Member

Mark Anthony Reynolds

Committee Member

Peter Erdman

Abstract

Ionospheric heating, accomplished by transmitting a high-frequency electromagnetic wave into the atmosphere, stimulates a large number of linear and non-linear wave-plasma interactions. One outcome of these interactions is the acceleration of thermal ionospheric electrons, leading to the production of induced optical emissions. Detection of these emissions yields information regarding wave-plasma interactions, which are of fundamental importance in many physical processes, and provides an effective means of remotely sensing ionospheric constituents and dynamics.

During an ionospheric heating experiment performed at the High Power Auroral Stimulation facility in Alaska (64.9° N, 146.8° W), a modified Czerny-Turner grating spectrometer acquired high resolution optical spectra of a heated volume. In addition to the already-documented 0(3P) 844.6 nm (excitation energy of 10.99 eV), and 0(5P) 777.4 nm (10.74 eV) emissions, two previously unreported radio-induced optical emissions, 0+ 732-733 nm (18.61 eV), and 0(3D°) 799.0 nm (12.49 eV), were observed. The experiment utilized a 2.85 MHz, 32 MW effective radiated power, o-mode radio wave, pointed into the magnetic zenith.

This thesis presents the first spectroscopic time series observations of a heated volume, showing optical emission modulation by the heater, and summarizes the current state of high-latitude ionospheric heating, with a focus on the generation and detection of optical emissions.

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