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An Experimental Study of the Hydromagnetic Waveguide


Hertel, Robert Henry (1965) An Experimental Study of the Hydromagnetic Waveguide. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/6RG2-ND30.


The hydromagnetic waveguide consists of a cylindrical metal tube filled with a longitudinally magnetized plasma. Among the classes of waves which propagate in this system are the compressional hydromagnetic modes, characterized by a waveguide cutoff at low frequencies and by a resonance at the electron cyclotron frequency. This paper presents the results of observations of the propagation of such waves in a decaying hydrogen plasma at frequencies from 0.8 to 3.4 times the ion cyclotron frequency. The phase shift and attenuation of the waves are interpreted in terms of the ion density and the temperature by applying a theory based on a three-fluid description of the plasma. Spectroscopic measurements of the H[subscript beta] line profile and absolute intensity are used to check the density and temperature inferred from the wave measurements. The results of this study indicate that a simple approximate relationship between the phase factor and density obtained by neglecting dissipation gives densities which agree well with the spectroscopic measurements. As a diagnostic tool this method may yield densities to within ? 25%, over a range of two decades. In the case of amplitude measurements only semiquantitative agreement between the wave and spectroscopic measurements is found, but the amplitude curves do show evidence of interferences between modes and a sharp cutoff at a critical density, both effects predicted by the theory.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Electrical Engineering and Physics)
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Electrical Engineering
Minor Option:Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Gould, Roy Walter
Thesis Committee:
  • Unknown, Unknown
Defense Date:21 January 1965
Record Number:CaltechETD:etd-04112003-095820
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1338
Deposited By: Imported from ETD-db
Deposited On:11 Apr 2003
Last Modified:08 Feb 2024 22:03

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PDF (Hertel_rh_1965.pdf) - Final Version
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