Numerical study of the normal current density behaviour in a narrow -   gap glow discharge
  A numerical study of normal glow discharge properties was performed in the case of small electrodes separations (0.05-0.4 cm) and moderate gas pressures (10-46 Torr). A recently observed new experimental effect of a considerable reduction in the normal current density for smaller discharge lengths was analyzed both by means of 2D fluid model and by a minimal 1D drift model of gas discharge. A good agreement between theoretical and experimental behaviour was demonstrated. An influence of the electrodes separation and of the gas heating on the value of the normal current density is discussed. 
S.A.Starostin, P.J.M. Peters, E.Kindel, A.V.Azarov, S.V.Mitko,   K.J.Boller