The Fluid Theory of Plasmas

Abstract

When the phase velocity of a wave excited in a plasma is larger than the thermal velocity, the main body of the plasma particles are out of resonance with the wave and the number of the resonant particles which exchange the energy with the wave is small. In this case, the plasma can be treated as a fluid. In the fluid plasma, the electron and ion fluids are supposed to be inter-penetrating each other. They interact through the electromagnetic field and exchange the momentum and energy through the collisions. Although transport coefficients based on collisional processes are given by the kinetic theory, transport coefficients associated with the waves excited 10 in the plasma are determined in the frame work of the fluid theory.