[en] A detailed analysis of an integral transport theory of electrons and ions in a gas in a field is presented. Different procedures allowing, in principle, the rigorous calculation of velocity distribution, drift velocity and diffusion coefficients are discussed. A derivation of a general expression for the transition probability, from a given velocity to another, which holds for any kind of collision, is given. Some questions linked to the convergence of iterative procedures of solution of some basic integral equations are also treated. (author)

[en] A stochastic approach to obtain the equation for the energy distribution of electrons in a gas in a field is discussed. A detailed analysis of the contribution that take account of the inelastic collisions is presented. The procedure is extremely simple but mathematically more rigorous than those available in the literature

[en] The author presents a Monte-Carlo simulation of electron swarm motion in a gas in an electric field. The motion has been analyzed to give all the quantities of practical and theoretical interest, e.g. drift speed, lateral and longitudinal diffusion coefficients, energy and spatial distributions, and linear correlation coefficients between position and energy. The results have been compared with solutions of Boltzmann's equation by Parker and Lowke, Skullerud, Lucas, Francey and Jones and with computer simulations by McIntosh and by Lucas and Saelee. The author considers only elastic collisions between electrons and atoms for which the collision frequency is given by a law of the form γ(epsilson)=βepsilonsup(n) and analyzes, in particular, the four cases n=-0.25, 0, 0.5, 1. In contrast with the results of Lucas and Saelee, it is always found that Skullerud's theory is the best. It represents well the temporal behaviour of the swarm and it is concluded that the need for improved solutions to Boltzmann's equation in order to represent the correct behaviour of electron swarms does not appear so important as several authors maintain. Possible reasons of the discrepancy between these results and those of Lucas and Saelee are discussed. (Auth.)

[en] The stochastic theory of electron transport in weakly ionized gases in absence of spatial diffusion is developed. Starting from the master equation, the Fokker-Planck equation for the energy distribution is obtained, first in the field-free gases, and subsequently in external fields. The problem of drift velocity is considered, and the theory is extended to the second order, taking also into account the effects of inelastic processes. (author)

No abstract available

[en] A Monte Carlo procedure for the calculation of velocity distribution and transport coefficients of electrons in a field in a gas is presented. The method competes with the best available techniques of numerical solution of the Boltzmann equation. Results relevant to the electron motion in N² are discussed. (author)

No abstract available

[en] A comparison between Monte Carlo and Boltzmann two-term calculations extended to all parameters of interest for swarm-experiment analyses on CO₂ is presented. It is quantitatively shown how multiterm calculations can improve the conventional results in this important but ''difficult gas''

[en] A Monte-Carlo analysis of the motion of electrons in argon is presented to test the conventional electron transport theory and, in particular, the debated theories pf parallel diffusion in a gas which lends itself very well to this end. The values of the ratio E/N between field intensity and atom number density are always so low that a high percentage of the electrons is in the energy region where discrepancies between Monte Carlo and theory may reasonably be expected. It is found, on the contrary, that the agreement is always very good for any E/N (i.e. within 3-4%) even for a cross section so strongly dependent on the electron energy as that recommended by Golden. The theories of parallel diffusion by Parker and Lowke, Huxley and, particularly, by Skallerud are shown to give accurate values of the diffusion coefficient D(parallel) even in cases where more than 80% of the electrons is in the (low) energy region, where the cross section is strongly decreasing with epsilon. (Auth.)

[en] Monte Carlo simulations have been used to assess the accuracy of the retarding field method used to unfold experimental electron energy distributions. It is shown that electron reflection at the electrode and extrapolation to zero energy of experimental data can explain, at least in part, the observed agreement between experimental and calculated energy distributions. Reasons for the good but not perfect agreement between theory and experiments in Ar at elevated E/N are discussed, together with the intrinsic limitations of the experimental retarding-field technique