Surface charge accumulation phenomenon at the gas-solid interface under DC voltage

In order to investigate the surface charge accumulation phenomenon at the gas-solid interface under DC voltage, the surface potentials of a cone-type insulator are measured using a capacitive probe after applying DC voltage to the insulator. The surface charge distributions under different voltage amplitudes and polarities are calculated. The experimental results show that surface charges do not accumulate significantly until the maximum electric field strength in the entire system reaches the initial discharge field strength, which implies the surface charges on the insulator are mainly generated by gaseous discharges. Moreover, the charge distributions are non-uniform due to the randomness of the discharges.