Nonlocal plasma electron hydrodynamics

A system of generalized equations is formulated for electron hydrodynamics in a plasma under conditions such that the electron mean free path is not small in comparison with the inhomogeneity space scale. The principal assumption underlying the derivation of these equations is that the deviation of the electron distribution function from local thermodynamic equilibrium is small. Electron collisions are investigated in the large ionic charge limit. The system of hydrodynamic equations is closed by the solution of the kinetic equation for electrons. Expressions for the Fourier components of the electron fluxes are given in terms of generalized forces, and for the first time nonlocal expressions are systematically derived for all the electron transport coefficients: electrical resistance, thermocurrent coefficient, thermal diffusivity, electron viscosity, friction force, and the ionic convection transport coefficients. Expressions are obtained for the longitudinal and transverse components of the electron susceptibility tensor over the entire range of perturbation scale lengths from the strongly collisional limit to the collisionless limit. These expressions are used to find the damping rate of an ionacoustic wave and the surface impedance of a semi-infinite plasma in the intermediate range of scale lengths. O 1996 American Institute of Physics. [S 1063-7761(96)012 10-31