ABSTRACT
Plasmas can be described as magnetohydrodynamic two fluids of ions and electrons with mass densities ρmi, ρme, charge density ρ, current density j, flow velocities V i, V e, and pressures pi, pe. These physical quantities can be expressed by appropriate averages in velocity space by use of the phase space distribution functions fi(r,v, t) of ions and electrons. The number of ions dNi in a small phase space volume dxdydzdvxdvydvz is given by
dNi = fi(r,v, t)dxdydzdvxdvydvz .
