On the basis of fluid approximation, a physical model in analytic form for dc glow discharge is presented. The model has yielded a variety of analytic expressions for the physical quantities concerned. These analytic expressions are functional, self-consistent, and satisfy all the governing equations as well as the real boundary conditions. With the builtin feature of mode indexing, the model may be employed for a wide range of applications. Several physically significant points which have not been reported previously were revealed from the present model.

Using the analytic expressions given in the preceding article, S. T. Pai [J. Appl. Phys. 71, 5820 (1992)] the concerned physical quantities n, N, V, Ez, Γ−, Γ+, and Jz and many others for dc glow discharges were calculated and systematically analyzed under various conditions. Several physically significant points have been brought forward via the analysis. Comparisons between the present results and the corresponding ones obtained by previous investigators showed similarities between them in many aspects. Such similarities signify the wide range applicability of the present model. The builtin feature of mode indexing in the model has been quantitatively demonstrated. Results yielded from such a demonstration are consistent with the corresponding physical situations.

The effect of dielectric surfaces on the breakdown voltage of gas spark gaps were investigated both theoretically and experimentally. Experiments have been carried out using N z and other gases at pressures ranging from one to five atmospheres. Several different dielectric materials ~ere used as substrates, having plain and cylindrical surface geometries. The observed results w.ere mte~preted by a physical model which was developed for this purpose. ~n t~e model, the maJ.or physical processes, i.e., electron production and electron loss due to diffusIOn, were treate~ m the. presence of the dielectric surface. In addition, electron loss due to electron traps on the dlelectnc surface has also been taken into consideration. The model yields an analytical expression for the breakdown voltage of a given gas spark gap. For the cases studied, the model predictions fit the observed results reasonably well.

On the basis of an analytic model developed previously [S. T. Pai, J. Appl. Phys. 71, 5820 (1992)], an improved version of the model for the description of dc glow discharge plasma was successfully developed. A set of closed form solutions was obtained from the governing equations. The two-dimensional, analytic solutions are functional and completely satisfy the governing equations, the actual boundary conditions, and Maxwell equations. They can be readily used to carry out numerical calculations without the necessity of employing any assumed boundary conditions. Results obtained from the model reveal that as the discharge gap spacing or pressure increases the maximum value in the electron density distribution moves toward the cathode. At a sufficiently large value of gap spacing, the positive column phenomenon begins to appear in the discharge region. The model has the capability of treating the positive column and negative glow as a continuous system without the necessity of studying them separately. The model also predicts a sharp rise of the positive ion density near the cathode and field reversal in the anode region. Variation of the electrode radius produces little effect on the axial spatial distribution of physical quantities studied.

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