Modeling of self-breakdown voltage statistics in high-energy spark gaps

Abstract

Articles you may be interested inInner surface flash-over of insulator of low-inductance high-voltage self-breakdown gas switch and its application Rev. Sci. Instrum. 85, 044709 (2014);Effect of electrode surface conditions on the selfbreakdown strength and jitter of a highpressure pulsed gas switch A model which incorporates the influence of electrode surface conditions, gas pressure, and charging rate on the voltage stability of high energy spark gaps is discussed. Experimental results support several predictions of the model; namely, that increasing the pressure and the rate of voltage charging both produce a broadening of the self-breakdown voltage distribution, whereas a narrow voltage distribution can be produced by supplying a copious source of electrons at the cathode surface. Experimental results also indicate that two different mechanisms can produce this broadening, both of which can be taken into account with the use of the model presented.Further implications of the model include changes in the width of the self-breakdown voltage probability density function as the primary emission characteristics of the cathode are modified by, for example, oxide or nitride coatings and/or deposits from the insulator. Overall, the model provides a useful and physically sound framework from which the properties of spark gaps under a wide variety of experimental conditions may be evaluated.

Development of a 5.4 MV laser triggered gas switch for multimodule, multimegampere pulsed power drivers

“…Electrode erosion will to some degree increase prefire rate, increase flashover rate, and/or increase optics degradation rate. Other switch operating conditions, such as gas pressure, affect the extent to which electrode erosion manifests into these failure modes [39].…”

Optimization of a Nanosecond Pre-Ionization Switch’s Breakdown Jitter Characteristic Based on a Probability Distribution Model of Electron Avalanche’s Initiation

“…The probability distribution model [18] of effective electron avalanche's initiation under pulsed electric field depends on both generating rate of initial electrons and normalized electric field E/p in the gap, which has a more complex form than that under DC electric field because the electric field under pulse voltage is time-varying [13].…”

“…The 6MV laser trigger switch used in ZR composes of a trigger gap and more than 20 cascade overvoltage gaps [11], the trigger gap first breaks down due to the laser pre-ionization, then the overvoltage gaps breakdown in sequence, the breakdown time delay jitter of the 6MV switch can be reduced to around 4ns [12]. Considering that the statistical time delay is the dominant part of breakdown time delay in a gas spark switch, the UV lamp can also be utilized to illuminate the cathode and reduce the statistical time delay jitter [13]. However, an external trigger system increases the complexity and cost of the whole generator and lowers its mobility.…”

High reliability low jitter 80 kV pulse generator

“…The prefire probability of a triggered gas switch at a given set of conditions is largely determined by that self-breakdown distribution function [7][8][9][10]. The jitter is usually a function of the fraction of the median self-break voltage (the voltage at which the probability of self-break is 50%) for a given trigger magnitude; switches operated closer to the selfbreakdown voltage are easier to trigger and thus have less variations in their run times.…”

“…This dictates a system that has a strong trigger mechanism that strongly initiates the output switch closure at a relatively low fraction of its self-breakdown voltage. The distribution of self-break voltage at a given pressure can be used to predict the reliability at lower voltages [8,9,15]. …”