Kinetic studies of thermal relaxation in plasma
The Lenard-Balescu equation is generalized for a magnetized plasma from the BBGKY hierarchy equation. The random phase approximation and the two time scale approximation are applied along with the neglect of essential 3-particle correlations. The generalized Lenard-Balescu equation is expressed in terms of binary collisions by the screened Coulomb force and the interaction between the individual particle and the collective mode. Weakly unstable cases which can be handled by quasilinear theory are contained in this treatment. The equation is solved numerically for a two-dimensional charged rod plasma with an external uniform magnetic field whose direction is along the charged rod. The thermal relaxation is measured by calculating the entropy of the system. Results are compared and agree qualitatively with ones from particle simulation. The Fokker-Planck equation is also solved numerically for a three-dimensional unmagnetized plasma. The diffusion and the friction coefficients are obtained. A multi-species plasma is studied. For a two-temperature plasma, the lower-speed portion of the hot plasma distribution overshoots, while the cold plasma is still relaxing to a Maxwellian. In both cases the slowing down of the relaxation rate is due to the relaxation times required for the filling of the high-speed tail.
- Research Organization:
- California Univ., Los Angeles (USA)
- OSTI ID:
- 7055940
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BBGKY EQUATION
FOKKER-PLANCK EQUATION
PLASMA
KINETIC EQUATIONS
NUMERICAL SOLUTION
RELAXATION
THREE-DIMENSIONAL CALCULATIONS
TWO-DIMENSIONAL CALCULATIONS
DIFFERENTIAL EQUATIONS
EQUATIONS
PARTIAL DIFFERENTIAL EQUATIONS
700103* - Fusion Energy- Plasma Research- Kinetics