Dust Ejection and Stream Formation via Cathode Spot Ignition at the Surface of a Dielectric-Covered Electrode

Cathode spots have been observed to form on an electrode surface covered with dielectric powder when biased at large negative voltages in the presence of a background plasma. The ignition of cathode spots leads to the ejection of the powder particles, which subsequently form dust streams. Particle imaging velocimetry (PIV) techniques are used to track the ejected particles and obtain the distribution of particle ejection velocities.