Boltzmann-equation analysis of electron kinetics in a positive column of low-pressure Hg–rare-gas discharges

Electron distribution functions have been calculated from a powerful numerical solution of the Boltzmann equation in the case of a positive column of low-pressure Hg--rare-gas discharge. The most important electron-atom collisional processes occurring in the plasma have been taken into account (elastic collisions, inelastic collisions including excitation, direct and stepwise ionizations, and also superelastic collisions). Coulomb interactions as well as atom-atom collisions leading to the creation of new electrons in the discharge (Penning reactions and Hg metastable-metastable ionizing collisions) are also considered. Then a comparative study of numerous methods of electron-distribution-function determination available in the literature has been carried out in the case of a Hg-Ar mixture followed by a discussion on the influence of several collisional processes on the electron-distribution-function calculation. The influence on the distribution-function calculation of the rare gas (He, Ne, Ar, Kr, or Xe) mixed with Hg has also been discussed in the case of a low-pressure positive-column fluorescent lamp discharge.