Dielectric current in a plasma

Tile ''dielectric'' current driven by a spatially dependent, suddenly applied, electric field E orthogonal (perpendicular to) to the magnetic induction B in a collisionless plasma is investigated from first principles. Both E and B are assumed in fixed directions. The current is qualitatively different in two conditions, whether del E<B(2)q/mc(2) or del E>B(2)q/mc(2) [K. D. Cole, Planet. Space Sci. 24, 515 (1976)], where q and m are the charge and mass, respectively, of charged particles. Here the current is verified in the first condition by a new argument. Nonadiabatically (NA) established uniform electric field orthogonal to a magnetic field causes an additional time-averaged pressure in the plasma, given by rho(m)c(2)E(2)/2B(2), where rho(m) is the mass density of the plasma, and a consequent accompanying additional magnetic moment per unit volume, given by -rho(m)c(2)E(2)/2B(3). When the electric field has a gradient parallel to the field itself, there is produced a dielectric current which is balanced by a grad p current due to the pressure caused by the electric field. This analysis of the NA case leads to the identification of div D-perpendicular to, rather than div E(perpendicular to), with the net charge density, consistent with the Jean's theorem of the equivalence of free particle orbit theory with the collisionless Boltzmann equation. In turn, this identification leads to the integral relation, along a line orthogonal to B in the direction of E, whether the latter is adiabatically or nonadiabatically established, p(perpendicular to)+(B-2/8 pi)-(rho(m)c(2)E(2)/2B(2))=const, instead of the conventional relation in which the electric field term is missing. (C) 1996 American Institute of Physics.