On the possibility of negative electron mobility in a decaying plasma

The electron energy distribution function and the electron drift velocity are studied numerically in a decaying plasma in the external electric field in the mixture Ar:F-2 = 1:0.005 at atmospheric pressure. For a reduced electric field strength over the range 0.055-0.55 Td the negative electron mobility was predicted earlier by the solution of the Boltzmann equation using the two-term approximation for the velocity distribution function. The applicability of this approximation for calculations of negative mobility is discussed. The Monte Carlo simulation method is used to verify results obtained from Boltzmann equation analysis. It is shown that there is a reasonable agreement between the Boltzmann equation and Monte Carlo results.