Meek’s Criteria For Breakdown Examined In Air Using A Needle-To-Plate Configuration

Meeks’ criterion established a relationship between the fields around space charges in an electron avalanche and enabled prediction of the breakdown voltage across a gap given its distance and surrounding gas pressure. This criterion is reevaluated in this study for atmospheric pressure with a non-uniform electric field distribution where voltage up to 30 kV is applied to a ring-to-plate electrode configuration. The ring electrode is made of a stainless-steel needle with an inner diameter of 0.25 mm and an outer diameter of 0.51 mm, and is vertically placed above a copper grounding plate for various gap distances ranging from 1 to 14 mm. The breakdown voltage vs. gap distance and the V-I characteristics are obtained for both cathode-directed and anode-directed streamer discharges. The experimental results are found to be in good agreement with analytical predictions based on Meek’s criteria for self-propagating streamer accounting for a non-uniform electric field distribution across the gap. The results are also compared with Paschen’s law. Emergent behavior such as the negative polarity producing breakdown at progressively higher voltage than the positive polarity at gap distances greater than 6mm is discussed. This analysis concludes that Meeks’ criteria held throughout our results, overall, and offers suggestions for further refinements to related models and experiments.