A theoretical investigation of the cathode fall in a neon glow discharge

Abstract

A theoretical analysis of the cathode fall experiments of Doughty and co-workers I Phys. Lett. A 103, 41 (1984); Apple Phys. Lett. 46, 352 (1985) J is presented, based on a Monte Carlo simulation of the electrons in the discharge. The nonlocal aspects of the electron kinetics (i.e., the average energy and the ionization coefficient) are emphasized and the connection is made with the work of Davies and Evans [J. Phys. D 13, L 161 (1980)]. Further examples of the electron kinetics are the light output in the negative glow and the electron energy distribution at the anode. The ion kinetics concentrate on the ion drift velocity and the molecular ion (Ne2~ ) formation.

Strict calculation of electron energy distribution functions in inhomogeneous plasmas

“…Such relaxation problems of electrons in homogeneous fields can be studied on the basis of expansion (2) and the resultant parabolic equation (6) for the isotropic distribution when adapting the kinetic study to these spatial relaxation problems. To enforce a disturbance in the velocity distribution, the anisotropic distribution f1 (ε, z) has been fixed at the position z = 0 by an appropriate boundary value f1 (U (ε, z = 0)) for which a Gaussian-like distribution is used.…”

“…To improve this situation intensive efforts [1][2][3][4][5][6][7] are currently devoted to this research field and in particular to the particle kinetics in inhomogeneous plasma regions. Typical examples of such plasma structures are the regions surrounding inserted grids, electrical probes and enforced plasma constrictions, the space charge field regions due to the plasma confinement by walls, the plasma regions where moving and standing striations occur and the discharge regions in front of the electrodes.…”

“…In recent years systematic studies of various problems connected with the kinetics of the electrons in inhomogeneous plasma regions could be succesfully performed. Due to the nonequilibrium nature the kinetic quantities of the electrons such as their velocity distribution function and the related macroscopic properties can only be found by solving appropriate electron kinetic equations [1][2][3][4] or performing adequate particle simulations [5][6][7] of the electrons.…”

The electron kinetics in the cathode region of H2/Ar/N2discharges

“…The electrons are supposed to be emitted from the cathode by the impact of singly charged ions only. Because of the expansion (11) and the resultant representation (19) the energetic distribution determining the emitted electron particle current density j z (z = 0) is given by the first contribution f 1 (U, z = 0) to the distribution anisotropy. This distribution component was fixed by the normalized boundary condition [20]…”

“…The non-equilibrium behaviour of the electrons in the cathode region of glow discharges has been studied experimentally and theoretically in several works [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. These studies have mainly been performed for discharges in rare gases, in particular, in helium, as well as for discharges in nitrogen [8,9] and hydrogen [18].…”