Plasma generation in the arc discharge with a thermionic cathode in current stabilization conditions

Abstract

Abstract The paper investigates plasma generation in a PINK plasma generator with thermionic and hollow cathodes under stabilizeddischarge current. The possibility of not completely closing of the thermionic electrons current into an external circuit is shown under these conditions. The current of emitted from the thermionic cathode electrons mostly closes inside the device, thus increasing the thermal and current load on the electrodes under such conditions. At this, the current direction in the hollow cathode circuit may change, which has no effecton external circuits. It is further shown that the redistribution of currents in the electrode circuits depends on the discharge conditions (including thermionic cathode heating current and voltage, as well as operating pressure and type of working gas), which, in turn, have influence on the instantaneous potentials of the cathode electrodes. Studies of the main plasma characteristics in different phases of the thermionic cathode heating current and under different plasma generation conditions have shown that changing the current direction in the hollow cathode circuit has in significant influence on the instantaneous values of the main plasma parameters, however, plasma generation is not optimalunder these conditions.