Monte Carlo Simulation of an Electron Swarm in an Argon-like Gas

A Monte Carlo simulation (MCS) of an electron swarm in an argon-like gas (of atomic mass a.m.u.), with Golden's cross section with a very deep minimum, is presented in order to examine the breakdown of the validity of the conventional two-term expression for the transverse diffusion coefficient Dr indicated by Milloy and Watts. It is found that the MCS value of Dr approaches the two-term value much slower than other swarm parameters such as the drift velocity Wand the longitudinal diffusion coefficient ~. The discrepancy between the MCS and two-term values of Dr revealed by Milloy and Watts is attributable to the evaluation of Dr at the long transient (correlation) stage in the MCS. It is concluded that the two-term expressions for Dr and ~ (and other swarm parameters) are sufficiently accurate even for Golden's cross section with a very deep minimum.

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Drift Velocity and Longitudinal Diffusion Coefficient of Electrons in CO2?Ar Mixtures and Electron Collision Cross Sections for CO2 Molecules

Australian Journal of Physics ◽

10.1071/ph950357 ◽

1995 ◽

Vol 48 (3) ◽

pp. 357 ◽

Cited By ~ 29

Author(s):

Y Nakamura

Keyword(s):

Diffusion Coefficient ◽

Momentum Transfer ◽

Cross Section ◽

Drift Velocity ◽

Cross Sections ◽

Vibrational Excitation ◽

Electron Collision ◽

Longitudinal Diffusion ◽

Excitation Cross Sections ◽

Momentum Transfer Cross Section

The drift velocity and longitudinal diffusion coefficient of electrons in 0�2503% and 1� 97% C02-Ar mixtures were measured for 0�03 ~ E/N ~ 20 Td. The measured electron swarm parameters in the mixtures were used to derive a set of consistent vibrational excitation cross sections for the C02 molecule. Analysis of electron swarms in pure C02 using the present vibrational excitation cross sections was also carried out in order to determine a new momentum transfer cross section for the C02 molecule.

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Monte Carlo Simulation of Electron Swarms in H2

Australian Journal of Physics ◽

10.1071/ph770083 ◽

1977 ◽

Vol 30 (1) ◽

pp. 83 ◽

Cited By ~ 24

Author(s):

SR Hunter

Keyword(s):

Monte Carlo Simulation ◽

Monte Carlo ◽

Diffusion Coefficient ◽

Cross Sections ◽

Inelastic Collision ◽

Lateral Diffusion ◽

Isotropic Scattering ◽

Transport Parameters ◽

Longitudinal Diffusion ◽

Experimental Values

A Monte Carlo simulation of the motio'n of an electron swarm in molecular hydrogen has been studied in the range E/N = 1,4-170 Td. The simulation was performed for 400-600 electrons at several values of E/N for two different sets of inelastic collision cross sections at high E/N. ,Results were obtained for the longitudinal diffusion coefficient DL , lateral diffusion coefficient D, swarm drift velocity W, average swarm energy <Ii) and ionization and excitation production coefficients, and these were compared with experimental data where available. It is found that the results differ significantly from the experimental values and this is attributed to the isotropic scattering model used in this work. However, the results lend support to the experimental technique used recently by Blevin et al. to determine these transport parameters, and in particular confirm their results that DL > D at high values of E/N.

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Computer Simulation of an Electron Swarm at low E/p in Helium

Australian Journal of Physics ◽

10.1071/ph740059 ◽

1974 ◽

Vol 27 (1) ◽

pp. 59 ◽

Cited By ~ 22

Author(s):

AI McIntosh

Keyword(s):

Computer Simulation ◽

Diffusion Coefficient ◽

Cross Section ◽

Electron Energy Distribution Function ◽

Recent Theory ◽

Electron Drift ◽

Longitudinal Diffusion ◽

Transverse Diffusion ◽

And Diffusion ◽

Momentum Transfer Cross Section

A computer simulated electron swarm at E/P293 = 1�0 V cm -1 tore 1 in a model gas has been used to examine the validity of a recent theory of electron drift and diffusion. The computed results are in agreement with well-established theories for the electron energy distribution function, drift velocity and transverse diffusion coefficient, and confirm that, for a constant momentum transfer cross section, the longitudinal diffusion coefficient is approximately half the transverse coefficient. However, significant differences have been found between the computed swarm and the predictions of the theory of Huxley (1972). In particular, over the time scale considered, the electron swarm is not symmetric about its centroid but is spatially anisotropic in such a way that it could appropriately be described as 'pear shaped'.

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