Light emission of droplet spots at vacuum arc and after arc extinction

Some droplets emitted by vacuum arc cathode spot and surrounded by dense plasma are referred to as droplet spots. The goal of this work is the study of spectral characteristics of the droplet spot light emission. The spectrum of droplets was compared with the spectrum of the cathode spot. The light emission of droplet spots after arc extinction was also studied. Non-monotonous (twinkling) glow of droplet spots was found to last for a long time (up to 1 ms) after arc extinction.