Doctoral Dissertations

Keywords and Phrases

Pulsed inductive plasmas; Spectroscopy; Theta-pinch; Triple probes

Abstract

The broad effort of the Missouri Plasmoid Experiment is to elucidate the energy conversion processes in a pulsed inductive discharge due to the presence of plasma. The test article is a 440 to 490 kHz theta-pinch (or solenoidal) geometry coil with a stored energy of around 80 joules. In this work experimental hydrogen, helium, argon and xenon data at back-fill pressures of 10 to 100 mTorr (1.3 to 133.3 Pa) are obtained and interpreted. Spectral and internal probe studies were performed on MPX Mk.I and Mk.II devices, respectively. IR spectra were acquired in the Mk.I device for argon and xenon. While triple probe studies on hydrogen, helium, argon, and xenon were performed in the Mk.II device.

Time-resolved electron temperature estimates for argon and xenon during the discharge time frame of 0 to 23 μs are obtained post-process via line intensity ratio methods. Experimental intensity ratios are compared with those of steady-state corona and collisional-radiative model assumptions. Electron temperature estimates were highly model dependent with the steady-state corona model yielding temperatures of around 10 eV or less and the collisional-radiative model yielding up to 100 eV.

Triple probe measurements provide both time- and radially-resolved electron temperature and density estimates for all four gases. Electron temperatures are seen to be limited to 20 eV on average with ionization fractions of up to 28%. In addition, probe currents show substantial evidence of a high charge density wave translating radially inward with speeds approximately given by the ion acoustic wave speed.

Finally, energy analyses of the triple probe results are performed and compared against circuit modeling efforts made previously on the same test article. Peak energy in combined electron heating and ionization accounts for on average around 25% of total dissipated circuit energy due to plasma. With the exception of xenon in which 40 to 90% was accounted for. "--Abstract, page iii.

Advisor(s)

Rovey, Joshua L.

Committee Member(s)

Gao, Jie
Tsai, Hai-Lung
Castano, Carlos H.
Kovaleski, Scott

Department(s)

Mechanical and Aerospace Engineering

Degree Name

Ph. D. in Aerospace Engineering

Publisher

Missouri University of Science and Technology

Publication Date

Summer 2015

Pagination

xiii, 86 pages

Note about bibliography

Includes bibliographic references (pages 80-85).

Rights

© 2015 Warner Charles Meeks, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Library of Congress Subject Headings

Plasma (Ionized gases)
Plasma engineering
Pinch effect (Physics)

Thesis Number

T 10761

Electronic OCLC #

921176842

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