Role of boundary conditions at the anode in the development of an electricfield induced avalanche in a gas at low pressure

A dc glow discharge configuration was investigated that includes a flat sem itransparent anode situated between two symmetrically positioned cathodes. The transparency of the anode increases the electron path length for ionizi ng collisions. This leads to a significant increase in the number of free e lectrons in the discharge volume. The simplicity of the discharge configura tion makes it possible to model the electron avalanche in its early stage w ith proper boundary conditions and without the use of adjustable parameters in both elastic and nonelastic scattering cross sections. The results obta ined for hydrogen indicate that the number of free electrons in the dischar ge can be increased by several orders of magnitude in comparison with a sim ilar discharge configuration but with an opaque anode. (C) 1999 American Va cuum Society. [S0734-2101(99)05006-X].