A plasma ignition plug for an internal combustion engine has a thorium alloyed tungsten anode separated from a vanadium- or beryllium-alloyed copper cathode by a boron nitride ceramic powder insulator. A generally semi-spherical titanium emitter is electrically coupled to the anode and disposed within an end of the insulator so as to form an annular gap with a torus on the end of the cathode. The surface of the emitter protrudes slightly beyond the rim of the torus on the cathode. High amplitude pulses driven into the anode arc across the annular gap to the cathode at more than twenty-four spots simultaneously, generating a plasma ignition front.