Detection of Excited States by Laser-Induced Fluorescence and Analysis of EnergyTransfer

摘要

The laser absorption technique was improved through the use of laser diodes andwas applied to absorption measurements of the line profiles for the A2 pi u from x 2 sigmag(+) transition of N2(+) ions to determine (a) the electric field strength in the positive column of pulsed discharges in N2 from the Doppler shift and broadening, (b) the time dependence of the density of ground state N2(+) ions drifting through N2 resulting from the transfer of kinetic energy of the N2(+) to rotational energy. An analysis of the impact of measurements made under this program on models of nonlinear ionization in N2 leads to the conclusion that ionization by collisions between pairs of metastable N2 molecules in the a' state probably make the largest contribution to the growth of instabilities in high-current discharges. (RH)