Browsing UAF Graduate School by Author "Xin, Wei"
An anomalous process of fast ionization of a barium shaped charge releaseXin, Wei; Swift, D. W.; Smith, R. W.; Kan, J. R. (1987-12)Fast ionization in excess of the photo-ionization rate appears to only occur when the barium shaped charge release is along the magnetic field direction. This thesis investigates the hypothesis that rapid ionization is caused by electrons heated in an ion cyclotron wave excited by the field-aligned streaming of barium ions through the ambient ionospheric plasma. The seed population of barium ions is assumed to be due to photo-ionization. The number density of barium ions due to photo-ionization is calculated. The plasma dispersion relation is derived based on the assumption of collisionless plasma. The excitation of barium ion cyclotron waves due to the interpenetrating of barium ions through the ambient plasma is investigated. It is proposed that the electrons are heated by the Doppler shifted waves via Landau damping. The Doppler shift is caused by an ambipolar electric field generated by the finite divergence of the injected barium neutrals.