Plasmatron includes an anode having a cylindrical proximal portion and a cylindrical distal portion, the distal portion having a smaller diameter than the proximal portion; a connecting portion connecting the proximal and distal portions and having walls oriented at 40-60 degrees to a center axis of the anode; a cathode having a generally cylindrical shape in its proximal portion and a tapering at a 30-45 degree angle to the center axis of the anode in its distal portion, with a cylindrical rod on its tip. Gap between the connecting portion of the anode and the distal portion of the cathode is double the gap between the proximal portion of the anode and the proximal portion of the cathode. High voltage power supply provides an operating voltage of 800-2500 volts and a current of 0.3-0.7 A. Length of the rod is approximately 1.5 times its diameter.