ELECTRON RATE COEFFICIENTS IN GASES UNDER NONUNIFORM FIELD AND ELECTRON-DENSITY CONDITIONS

The theory of perturbation is used to describe electron rate coefficie nts in gases under non-uniform field and electron-density conditions w hen the deviation from spatial uniformity is small. It is shown that t he space-dependent rate coefficients can be represented as a sum of th e local values and the product of new rate coefficients dependent on t he local field and the gradients of the field and of the electron dens ity. By solving the Boltzmann equation in a two-term approximation, th e new rate coefficients are calculated for N-2, CO2, and Ar. The resul ts of our calculations are compared with experimental data on the rela tive excitation rates in a steady-state Townsend discharge in a CO2:N- 2:He:CO mixture and with results of previous Monte Carlo simulations o f the electron swarm behaviour in non-uniform fields.