By application of a specially designed trigger electrode on which a laser beam is focused, it is possible to obtain a reliable method for initiation of high voltage vacuum discharges. The trigger electrode plasma generated by the laser beam has been studied with regard to its light emission. The result proved that the light intensity reaches its peak value about 200 ns after application of the laser trigger pulse. In addition, by using the triggering method presented, investigation of the high voltage vacuum discharge characteristics—current derivative(dI/dt),current, and x-ray output versus time—has been carried out. Recorded traces indicate pinching of the inter-electrode discharge channel but also x-ray emission during this event. ©1997 American Institute of Physics.