Ionization and Deionization of Electron Beam Disturbed Air

Abstract

An air plasma generated by the passage of a pulsed electron beam is a discharge which is not in equilibrium. Where the electron T_e, the vibrational T_v, and the gas T_g temperatures are not equal. The interaction of the beam electrons with the air molecules generates a conductivity and a density channel which exemplifies the disturbed air phenomena. The formation of these channels and their relaxation depend on ^1,2 a host of atomic and molecular processes which ensue in air, during and after the passage of the beam. These processes, stated briefly, proceed as follows. The beam and secondary electrons ionize, dissociate, excite the internal modes of N₂ and O₂ and produce the bulk of the plasma electrons during the passage of the beam. The beam also heats the channel through direct atomic processes and by ohmic heating of the plasma electrons which in turn heat the ions and neutrals by elastic collisions. The evolution of the conductivity and the density channel proceed, after the passage of the beam, by dissociative recombination, charge exchange, quenching of electronic states, clustering, ion-ion recombination, neutral atomic recombination, vibrational-translation energy exchange and channel expansion.