Electric field non-uniformity effect on dc low pressure gas breakdown between flat electrodes

Abstract

This paper presents the results of studying the gas breakdown in a non-uniform direct current electric field. The breakdown curves have been measured in nitrogen between flat electrodes of 6 mm in radius spaced 3–300 mm apart and placed inside the discharge tubes of 6.5 mm and 28 mm in radius.The effects of the non-uniform distribution of the electric field inside the inter-electrode gap and of the diffusion loss of charged particles to the discharge tube walls on the gas breakdown have been studied separately. A conclusion is drawn from the experimental data that the general form of the gas breakdown criterion must be as follows U=fpL,L/Rel,L/Rtubein which the L/Rel ratio of the inter-electrode gap value to the electrode radius describes the electric field nonuniformity inside the discharge tube whereas the L/Rtube ratio characterizes the diffusion loss of electrons on the discharge tube walls.It has been found that the breakdown curves for different electrode radius values and a fixed gap L value intersect at such value of the gas pressure that corresponds to the location of the inflection point of the breakdown curve for a uniform electric field.