Influence of the finite mass-ratio on the charged-particle transport in gases

The effects of the mass ratio m/M on the swarm parameters are investigated in the case of a constant collision frequency model. Here, m and M are the masses of a charged particle and a neutral molecule, respectively. Expressions for the swarm parameters are derived from the simple kinetic theory without use of a complicated stochastic equation, i.e., Boltzmann equation. Present theoretical results are shown to be in remarkable agreement with those of the recent simulation by Ikuta et al. (author)