Investigation of Multi-Photon Excitation in Argon with Applications in Hypersonic Flow Diagnostics

<p>Non-intrusive flow diagnostics are essential for studying the physics of hypersonic flow wake regions. To advance the development of next generation hypersonic vehicles and to improve computational fluid dynamics techniques in the hypersonic regime, NASA needs a suitable non-intrusive diagnostic technique to measure velocity, density, and temperature. We will present our work on developing a seedless, non-intrusive diagnostic technique using excited state argon atoms, prepared via multi-photon excitation. In this dissertation, we report results on the first phase of this hypersonic wake measurement project. In particular, we have redesigned and characterized the performance of a high energy, nanosecond pulsed Ti:Sapphire laser. Using this laser, we have studied in argon, a three-photon excitation that yields a long-lived metastable state via radiative decay. Our measurements were conducted over a range of pressures both with and without a krypton buffer gas. We compare our measured results to detailed calculations of the excitation pathway and describe the physical processes that govern the excitation and decay processes. Finally, we provide a roadmap for the next phase of the project.</p>

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Year dc:date.available

2016

Author dc:creator

• Mills, Jack L.

Contributors dc:contributor

• Charles I. Sukenik
• R. Jeffery Balla
• Lepsha Vuskovic
• Ted Rogers
• Gordon Melrose

• Flow diagnostics
• Fluid dynamics
• Hypersonic flow wake regions
• Hypersonic vehicles
• Ti:Sapphire laser
• Atomic, Molecular and Optical Physics

Statement dc:rights

• <p>In Copyright. URI: <a href="http://rightsstatements.org/vocab/InC/1.0/">http://rightsstatements.org/vocab/InC/1.0/</a> This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).</p>

Identifier

9781369560152

OAI identifier oai:identifier

oai:digitalcommons.odu.edu:physics_etds-1005