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Experimental Study of Plasma Wave Resonances in a Hot Nonuniform Plasma Column


Nickel, John Carl (1964) Experimental Study of Plasma Wave Resonances in a Hot Nonuniform Plasma Column. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/4TNV-Z616.


The relative frequency spectrum ω2p of plasma wave resonances in the positive column of a low pressure mercury discharge tube has been shown to depend upon the parameter r2wD where rw is the radius of the column, λD is the Debye length defined in terms of the average electron density, and ωp is the square of the average plasma frequency. This paper presents observations of both dipole and quadrupole resonance spectra made on several discharge tubes with rw ranging from 0.30 to 0.87 cm. For these measurements r2wD varies from about 102 to 105, and the best fit electron temperatures are found to be of the order of 3 ev. The average electron densities are directly measured using a cavity perturbation technique.

The results of these observations are found to be in good agreement with the theory based upon the first two moments of the correlationless Boltzmann equation in conjunction with Parker's electron density profile for a low density positive column. The results of a preliminary investigation of the effects of an axial, static magnetic field on the dipole resonance spectrum are also presented. These results indicate that in the presence of an axial magnetic field not only does the lowest resonance (approximately predicted by the cold plasma theory) split, but the next higher order resonance also splits. For the lowest resonance, it is found that Δω/ωg ≈ .8 ± .1, while for the next higher order resonance Δω/ωg ≈ .5 ± .2, where ωg is the cyclotron frequency. These preliminary results are in good accord with calculations made by Parker, again using the moment equation approach.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Physics)
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Gould, Roy Walter
Thesis Committee:
  • Unknown, Unknown
Defense Date:27 May 1964
Funding AgencyGrant Number
Office of Naval Research (ONR)220(50)
Record Number:CaltechETD:etd-10182002-102050
Persistent URL:
Related URLs:
URLURL TypeDescription ItemElectron Tube and Microwave Laboratory Technical Report 22
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:4153
Deposited By: Imported from ETD-db
Deposited On:21 Oct 2002
Last Modified:19 Jan 2024 23:38

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