A vacuum arc plasma source based on cathode-anode cooperative discharge

Abstract Multi-element vacuum arc plasma sources have found extensive applications in numerous fields due to their ability to simultaneously generate multiple elemental ions. This paper carried out experimental research on the discharge characteristics in a vacuum arc plasma source based on cathode-anode cooperative discharge, which can produce multiple elemental ions. In the experiment, tungsten was used as the cathode and aluminum as the anode. Both electrodes are rod-shaped with a diameter of 1 mm, and the interelectrode spacing is set to 1 mm. Experimental results indicated that a disc-shaped plasma cloud could be observed at 2μs in the interelectrode region caused by the collision and accumulation of plasmas derived from the cathode and anode. The multispectral thermal imaging was used to measure the spatiotemporal distribution of the anode surface temperature during the discharge process. The results showed that the temperature in some areas of the anode increased to the melting point in 1μs, leading to a high density of anode vapor. The area of the high-temperature region on the anode expanded with time. The interelectrode electron temperature was in the range of 1-2eV, increasing from the cathode to the anode when the disc-shaped plasma cloud appeared. This was because the anode vapor could reduce the arc conductivity and consequently significantly increase the Joule heat. At the end of the article, the samples coated using the above-mentioned device are shown. The coating is relatively uniform with minimal droplet content. The vacuum arc plasma source proposed in this paper can be used to generate multi-element plasmas with the advantages of simple structure and controllable products.