Formative Time Delay in Nitrogen Discharges at Low Pressure

Abstract

In this paper the formative time delay in nitrogen was determined from statistically based measurements of electrical breakdown time delay. The measurements were carried out under different conditions on a newlydesigned gas tube with a plane-parallel electrode system made from copper. The avalanche growth was followed based on a simple analytical model agreeing well with the experimental data. The dependencies of the formative time delay on the working voltage and the electron yields in the interelectrode space originating from residual states were found. A developed approximate model for the formative time delay has shown fits with the experimental data better than other models discussed in the literature.

Determination of correlation coefficient of the statistical and formative time delay in nitrogen

“…The σ ts (τ ) = 1/Y (τ ) dependence (with P ≈ 1 at a given working voltage) to about 10 ms of region III of the memory curve (figure 1) is approximately linear in semilog scale confirming that a secondary electron yield in the interelectrode space is determined by the nitrogen ions decaying by diffusion [5,6]. After that, in region III, the dominant emission mechanism of electrons initiating breakdown is the surface recombination of nitrogen atoms remaining from the preceding glow [5,21].…”

“…Depending on the level of preionization, the Gauss-exponential and Gaussian distribution of the statistical time delay were obtained and theoretically based on a binomial distribution for the occurrence of initiating electrons. The dependence of the formative time on working voltages and relaxation time in nitrogen is presented in [5]. The formative time was determined from measured time delay data in the manner 1 Author to whom any correspondence should be addressed.…”

“…described in [6] and fitted by the model based on exponential growth of the electron current density from a cathode [5].…”

Voltage dependent models of the formative time delay in argon

“…where 0 i n is the initial ion number density. According to (12), the ion number density it n , which corresponds to the transition from negligible to non-negligible space charge and the electric field distortion (Marković et al, 2007), can be written as:…”

“…The electric field distortion by non-negligible space charge in the later stages of avalanche growth leads to rapid changes in the current and voltage. However, the fast current rise time is of the order of several microseconds and its contribution to the f t could be neglected (Marković et al, 2007). Fig.…”