Raimund Summer

Streamer propagation in hybrid gas-solid insulation

The influence of a solid dielectric barrier on development of an electrical discharge in air between needle and plane electrodes is analyzed by means of computer simulations. The computational model describing formation and propagation of a streamer in atmospheric air and accounting for charge transport and trapping on barrier surfaces is presented. The results of the simulations performed for 5 cm air gap containing solid barrier (plate) inserted between the needle and plane electrodes are discussed focusing on discharge dynamics and associated electric fields.

Streamer branching in air: Physical model and simulations in fully 3D spatial domain

Fully coupled self-consistent model of streamer branching is presented. The model incorporates inhomogeneities in gas media representing, e.g., large molecular clusters, micro dust particles, etc., which act as centers for localized space charge build-up. The results of the performed simulations show that charge accumulation at such centers leads to their electrostatic interactions with the streamer head and causes its splitting. Quantitative analysis of the dynamics of charge carriers densities, generated space charges and magnitudes of the electric fields associated with the branching process is presented.