Theoretical Structure of Plasma Equations and Application to a Simple Problem.

with i = 1 for electrons and i = 2 for ions. They thereby neglect the terms (Wi/6t)e0.1 normally on the right-hand side of these equations, apparently justifying themselves by the fact that the plasma is "sufficiently dilute." But the dilute condition of the plasma in no way suffices to make (bfi/bt)Xin negligible in their effect on the motion of the plasma. When the single transport equation is written for a gas of uncharged particles, then the reduction of "collisions" by "sufficient dilution" will justify the elimination of the (6fi4/t),01n from the equation. But when the gas is made up of two types of particles, oppositely charged, the relative motion of the one type to that of the other type can give rise to forces per particle which do not vanish with the density of the gas. The motion of one type of particles relative to the other gives rise to microscopic high frequency electromagnetic fields which will react upon the other particles with a force per particle which will not approach zero as the density of the particles approaches zero, so long as the plasma as such has a physical meaning. The Corrected Transport Equations.-Let us write the corrected equations (R & R 4) as