Higher order collision frequencies as corrections to Maxwellian distribution function

Abstract

Mono-energetic collision frequency for electrons colliding elastically with various ionospheric target gases is averaged over generalized Laguerre functions with appropriate weighing factor. These distribution functions are chosen because they form a complete orthonormal set over an infinite energy range in which a function like collision frequency, at a particular energy, can be expanded The expansion coefficients are the higher order collision frequencies. These have been calculated for electrons colliding with neutral targets The higher order collision frequencies are measures of the amount of deviations from the dominant Maxwellian distribution when the conditions are slightly away from the thermal equilibrium. The main result obtained is that even at low electron temperature, the assumption of Maxwellian distribution is inadequate when the cross-sections vary rapidly with electron energy.