Splashing conditions for a liquid metal in vacuum arcs: Cyclic processes in a cathode spot. (January 2019)

• Record Type: Journal Article
• Authors: Gashkov, M A; Mesyats, G A; Zubarev, N M
• Is Part Of: Journal of physics. Volume 1147(2019)
• Publication Date: 2019-01
• Subjects: Physics -- Congresses; 530.5
• DOI: 10.1088/1742-6596/1147/1/012125
• Languages: English
• ISSNs: 1742-6588

Abstract

Abstract: Molten metal extrusion from craters that form on the cathode during vacuum arc burning is considered. Using the hydrodynamic similarity principle, this process is compared with the well-studied splashing process that can develop within the impact of drops impinging one by one on a solid surface (the arc cycle duration is identified with the inverse frequency of the drop train). Based on this analogy, the conditions under which the regime of spreading of a liquid over the cathode surface will change into the splashing regime (accompanied by the formation of microjets and droplets) are analyzed. As it turns out, the conditions realized in vacuum arc cathode spot at near-threshold currents are close to the splashing threshold of liquid metal. This gives grounds to relate the existence of a threshold arc current to the existence of a threshold for the process of liquid metal jet formation.