Hydrodynamic equations for a plasma in the region of the distributionfunction plateau
Abstract
A hydrodynamic theory is presented for plasma particles whose distribution function is close to a plateau in some phasespace region for a finite onedimensional phasespase interval. In the framework of the methods of moments, a series expansion of the particle distribution function in an appropriate system of orthogonal (Legendre) polynomials near the state with a plateau is carried out. Deviations from the plateau are due to the presence of a heat flux. The expansion obtained for the distribution function is used to truncate the chain of hydrodynamic equations and to calculate the additional terms arising from the finiteness of the phase interval. The case of onedimensional Langmuir turbulence is considered as an example. Expressions are presented for the moments of the quasilinear integral of collisions, which describe the variations of the macroscopic characteristics of resonant particles in the respective hydrodynamic equations. Criteria for applicability of the equations obtained are presented. Approximate invariants of motion are obtained in the extreme cases of narrow and broad plateaux.
 Publication:

Journal of Plasma Physics
 Pub Date:
 October 1989
 DOI:
 10.1017/S0022377800014343
 Bibcode:
 1989JPlPh..42..257K
 Keywords:

 Distribution Functions;
 Hydrodynamic Equations;
 Legendre Functions;
 Plasma Physics;
 Heat Flux;
 Spatial Distribution;
 Stress Tensors;
 Transport Theory;
 Plasma Physics