{"title":"Features of the Structure of Spark Channels in a Near-Cathode Region","authors":"E. V. Parkevich","doi":"10.1134/S0021364024602951","DOIUrl":null,"url":null,"abstract":"<p>Features of the generation of a highly ionized plasma from a tip cathode after the electrical breakdown of a millimeter air discharge gap at atmospheric pressure have been studied using picosecond laser probing at a wavelength of 532 nm. It has been found that the transformation of a micron-sized cathode spot to a growing spark channel is accompanied by the formation of a spherical plasma region in the base of the spark channel in the near-cathode region. The electron density in this region, which is about 100 μm in diameter, decreases to 3 × 10<sup>19</sup> cm<sup>–3</sup> in the center and increases to (5–6) × 10<sup>19</sup> cm<sup>–3</sup> in its shell with a thickness of about 20 μm. It has been shown that the growth of the subsequent spark channel is governed by a strong ionization front formed at the boundary of the expanding spherical plasma region in 1 ns after the gap breakdown. It has been assumed that the formation of the spherical plasma region in the near-cathode region affects the subsequent development of the microstructure of the electric spark.</p>","PeriodicalId":604,"journal":{"name":"JETP Letters","volume":null,"pages":null},"PeriodicalIF":1.4000,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"JETP Letters","FirstCategoryId":"101","ListUrlMain":"https://link.springer.com/article/10.1134/S0021364024602951","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"PHYSICS, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Features of the generation of a highly ionized plasma from a tip cathode after the electrical breakdown of a millimeter air discharge gap at atmospheric pressure have been studied using picosecond laser probing at a wavelength of 532 nm. It has been found that the transformation of a micron-sized cathode spot to a growing spark channel is accompanied by the formation of a spherical plasma region in the base of the spark channel in the near-cathode region. The electron density in this region, which is about 100 μm in diameter, decreases to 3 × 1019 cm–3 in the center and increases to (5–6) × 1019 cm–3 in its shell with a thickness of about 20 μm. It has been shown that the growth of the subsequent spark channel is governed by a strong ionization front formed at the boundary of the expanding spherical plasma region in 1 ns after the gap breakdown. It has been assumed that the formation of the spherical plasma region in the near-cathode region affects the subsequent development of the microstructure of the electric spark.
期刊介绍:
All topics of experimental and theoretical physics including gravitation, field theory, elementary particles and nuclei, plasma, nonlinear phenomena, condensed matter, superconductivity, superfluidity, lasers, and surfaces.