The properties of vacuum gap closure initiated by a plasma cathode are presented. The plasma cathode consisted of approximately 60 surface flashover sites distributed over a 10‐cm2area. Vacuum gap dimensions were 1×7.5 cm in diameter. Faraday cup measurements indicated an ion density greater than 1012cm−3, which was controllable by the amplitude of the initiating high‐voltage pulse. Although the field‐free expansion velocity of the plasma was measured to be 7 cm/&mgr;s, plasma‐cathode‐initiated closure of the vacuum gap indicated closure speeds on the order of 0.5 cm/&mgr;s. Also, increased injected ion density and increased anode‐cathode potential resulted in increased closure velocity.