Research Progress of Model of Vacuum Arc and Anode Activity Under Axial Magnetic Fields

Modeling and numerical simulation is an important tool for the research of the physical mechanisms of the vacuum arc (VA). Compared with the experiments of the VA, numerical simulation is more efficient and economical. Axial magnetic fields (AMFs) are also the most popular control technology in vacuum interrupters and other application fields. First, the model of VA was reviewed from a relatively simple zero-order one to 2-D one, and then a 3-D one, which gives us a more comprehensive understanding of VA. Second, the influence of spatial distribution of magnetic fields on VA behavior is also studied. VA behavior under different commercial AMF contacts was simulated and compared based on 3-D magnetohydro-dynamic model. Influence of the radial slots and magnetic field generated by adjacent phase and bus bar on arc characteristics has been reviewed. Third, the VA modeling with active anode is reviewed and discussed. Anode vapor can cool arc plasma, and leads to changed distribution of current density and plasma parameters. Model and simulation technology of anode activity have also been reviewed in this paper, from 1-D, 2-D, to 3-D, and then the deformation of anode melting pool is considered. Deformation of anode melting pool will make anode temperature more reasonable. Finally, the challenge and research direction of VA modeling is also given and discussed.

I. Introduction

Vacuum arc (VA) is the metal vapor arc in the vacuum environment, which appears in many fields, such as, vacuum interrupters, ion sources, coatings, thrusters, and accelerators. VA can be simply divided into three regions, which are cathode spots and mixing region, arc column regions, and anode regions. When the arc current is not very high, the cathode spots are the main plasma source of arc column, and when the arc current is very high, anode will become very active, and anode melting and evaporation will become significant, anode will become another plasma source. For gas arc, such as air arc and SF₆ arc, the gas blowing technology always is adopted as the arc extinguishment tool. Different from gas arc, magnetic field always is adopted to control the VA. At present, axial magnetic field (AMF) and transverse magnetic field (TMF) are the popular controlling technologies of VA. Experiments still are the main research tool of VA, while modeling and simulation technology has gotten the rapid progress in recent years. In this paper, modeling and simulation of VA and anode activity under AMF will be mainly reviewed. The challenge of VA modeling in the future will also be discussed.