Citation
Kenny, John J. (1968) Electric dipole radiation in isotropic and uniaxial plasmas. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd09242002082113
Abstract
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This paper describes an investigation of radiation from an electric point dipole situated in a cold, collisionless, homogeneous, electronic plasma medium. Two limiting cases of a gyroelectric medium are studied. The magnetostatic biasing field [...] is first taken to be equal to zero, making the medium isotropic, and then it is taken to be infinite, causing a uniaxial anisotropy. The retarded electromagnetic fields and the instantaneous and averaged values of irreversibly radiated power [...] are calculated.
In each medium, the partial differential equations resulting from the twosided Laplace transformation of Maxwell's equations with an oscillating electric dipole source and the constitutive equations (derived from the appropriate form of the Lorentz force equation) are solved. A particular path deformation of the Laplace inversion integral reveals that the electromagnetic fields and [...] are exactly expressible in terms of circular, cylindrical, and twovariabled Lommel functions. Asymptotic expressions and graphical results of numerical calculations of these quantities are presented.
For the isotropic case, it is shown that the retarded fields are well behaved for all space and time (excluding the origin, of course). [...] eventually settles down to the result derived from the conventional timeharmonic analysis when the dipole oscillation frequency [...] is greater than the plasma frequency [...] . When the value of [...] is less than that of [...], [...] eventually oscillates at a frequency [.....] with zero average value.
When the medium is uniaxial, the fields are finite everywhere except at the dipole. The amplitude of the fields does, however, increase with increasing time. This is quite different from the ordinary timeharmonic solution which ignores all time variations different from [...] and which is singular on a conical surface defined by [...] for [...]. The value of [...] in a uniaxial medium is found to be equal to the value of [.....] of a dipole in vacuum. It is also shown that the socalled conventional expression for timeaveraged radiated power will not give a sensible result since it contains the retarded electric field which never settles down to a steadystate variation with time. The quantity [...], on the other hand, does not increase with time, oscillates only at the source frequency, and has a welldefined time average.
Item Type:  Thesis (Dissertation (Ph.D.)) 

Degree Grantor:  California Institute of Technology 
Division:  Engineering and Applied Science 
Major Option:  Engineering and Applied Science 
Thesis Availability:  Public (worldwide access) 
Research Advisor(s): 

Thesis Committee: 

Defense Date:  19 April 1968 
Record Number:  CaltechETD:etd09242002082113 
Persistent URL:  http://resolver.caltech.edu/CaltechETD:etd09242002082113 
Default Usage Policy:  No commercial reproduction, distribution, display or performance rights in this work are provided. 
ID Code:  3737 
Collection:  CaltechTHESIS 
Deposited By:  Imported from ETDdb 
Deposited On:  25 Sep 2002 
Last Modified:  26 Dec 2012 03:02 
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