Initial Stages of Negative Point-to-Plane Breakdown in Helium

Measurements have been made of the initial stage of breakdown in a short negative point-to-plane gap in helium at pressures of 50-600 Torr. The transient glow discharge establishment was found to be preceded by a peaked current signal of conspicuous similarity to the Trichel pulse rise and its initial decay in an electronegative gas. The results are interpreted as a possible indication for the unification of these breakdown-phenomenon mechanisms on the conceptual basis of the primary cathode-directed streamer.