Method to determine rotation velocity of constricted vacuum arcs driven by transverse magnetic field

The objective of this paper is to propose a new method to quantitatively determine the arcing rotation velocity of the constricted vacuum arc driven by a transverse magnetic field (TMF). This method is based on a split anode and TMF cathode configuration system. Experiments were set in a demountable vacuum chamber. Both electrodes have a contact diameter of 60 mm. The anode surface was divided into four regions: one central region (Area I) and three symmetrically peripheral annular regions (Area II, III and IV). The currents of the four areas on the anode contact were measured using four Rogowski coils situated outside the vacuum chamber. The observed arc modes were recorded by a high-speed CCD video camera. The rotation velocity of the constricted arc column is calculated from the arc current waveforms of the four split areas. The experimental results indicate that the maximum speed is approximately 471 m/s with the arc current of 16 kA rms. The results also reveal the corresponding anode current distribution characteristics under TMF in different arc stages during the arcing time.