Discharges triggered on and by electron bombarded dielectrics

Secondary discharges were obtained on precharged dielectrics and between biased metallic electrodes close to a primary discharge. Laboratory simulations of environmental changes (pressure, illumination) were performed to provide insight into the in-situ phenomena. Experiments with a proton beam do not confirm any of the expectations that had been put forward. The experiments to determine the pressure increase caused by a discharge and its importance in the propagation lead to an ambivalent conclusion. On the one hand, the pressure increase is important enough to trigger a discharge on a precharged sample. On the other hand, the expansion gas velocity is too low to compare with the propagation velocity. Experiments with the two samples, one of which was enclosed and shielded by a grid, are much more satisfactory. They point to the responsibility of particles, not fields, in the discharge propagation process. In particular, the ions are shown to play the most important role