The Arc Characteristics in an Insulated Constrictor Nozzle

The magnetic body force and the gasdynamic drag force act on the arc column of the plasma jet generator. For a stable operation, the magnetic body force must be balanced by the drag force. When an increase of the magnetic body force occurs, the anode arc terminus goes back into the nozzle inlet and the effective arc gap is decreased. The insulated constrictor nozzle is used to prevent the retreat of an anode spot and the arc column is forced to elongate until the anode arc terminus locates at the nozzle exit region. The voltage-current characteristics of the elongated arc is a rising characteristics and the net input power supplied to the arc is increased effectively. The heat loss of the insulated constrictor is 20% of the anode loss and the efficiency of the insulated constrictor section is 80&acd