Effective coffision frequency and electron temperature in a weakly ionized argon plasma

Herein is described a calculation of the effective coffision frequency ν_eff of a low- density, shock-heated argon plasma under the influence of a weak electric field which oscillates harmonically with angular frequency ω. It is shown that, for the high frequency case ω > where is the collision frequency in a Maxwellian gas plasma, one has ν_eff 2, provided that the imaginary part of the argon plasma conductivity is negligibly small in comparison to the real part. The influence of the theoretical model used to calculate ν_eff on the values of the electron temperature T_e derived from measurements is compared with the results obtained in a data reduction for which the hard-sphere model for particle encounters was utilized.