Some aspects of whistler wave interactions in magnetized plasmas
This thesis considers some aspects of whistler wave interactions in magnetized plasmas. Choosing the whistler frequency to be in the lower-hybrid range i.e., omicron/sub 1/ << omega/sub 0/ << ..cap omega../sub e/ (..cap omega../sub ..cap alpha../ is the cyclotron frequency of species ..cap alpha.. and omega/sub 0/ is the whistler frequency), the following aspects are studied: Scattering of a coherent whistler from random density fluctuations is considered following a perturbation method due to Keller. The attenuation length of a whistler wave is calculated for a drift-wave-type fluctuation model and is simply expressed as a function of its propagation angle in the limit of long whistler wavelength compared to a correlation length. For typical tokamak and space plasmas, plots of the attenuation length versus the angle show that scattering becomes important as the angle increases. Steady-state self-modulation of a coherent whistler wave is next investigated. In a typical tokamak situation the whistler envelope is found to be modulationally stable, so that no solitons could form. Furthermore, treating the plasma gradients perturbatively, a nonlinear Schroedinger-type equation is obtained. The behaviour of the nonuniformity function reveals that for typical gradient profiles in tokamaks, this function could be more or less approximated by a form amenable to exact solution, implying that one could follow an analysis similar to Leclert et al. in the whistler case also. It is also found that the solitons could form only if the propagation angle of the whistler is less than 54.7/sup 0/. The estimates of the threshold for soliton formation and its size are given for typical space plasma parameters.
- Research Organization:
- Clarkson Coll. of Tech., Potsdam, NY (USA)
- OSTI ID:
- 6211638
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
PLASMA
WHISTLERS
ATTENUATION
BRILLOUIN EFFECT
CYCLOTRON FREQUENCY
PARAMETRIC INSTABILITIES
PERTURBATION THEORY
SCATTERING
SCHROEDINGER EQUATION
SOLITONS
TOKAMAK DEVICES
WAVE PROPAGATION
CLOSED PLASMA DEVICES
COHERENT SCATTERING
DIFFERENTIAL EQUATIONS
ELECTROMAGNETIC RADIATION
EQUATIONS
INSTABILITY
NOISE
PARTIAL DIFFERENTIAL EQUATIONS
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
QUASI PARTICLES
RADIATIONS
RADIO NOISE
RADIOWAVE RADIATION
THERMONUCLEAR DEVICES
WAVE EQUATIONS
640430* - Fluid Physics- Magnetohydrodynamics