Stability of Corona Discharge in High Pressure Nitrogen

The study of corona discharge is important for successful development of various electrostatic technologies. The current study is directed at investigating the stability of a negative polarity direct current corona discharge in high pressure nitrogen. Experiments were carried out at test set-up equipped with a high temperature high pressure (HTHP) corona discharge ionizer which has star-shaped disk high voltage electrodes installed inside of a cylinder grounded electrode. The “direct” and “indirect” current–voltage characteristics (CVCs) were measured for various gas pressure values without and with a gas flow through the HTHP set-up casing and without external heating of the ionizer grounded electrode. An increase of gas pressure results in an increase of a “CVC-direct” onset voltage and in a decrease of the corona current at a constant value of the applied voltage. A hysteresis effect is observed for the corona discharge CVCs at a high gas pressure when corona currents for the “CVC-indirect” are measured at voltages lower than the “CVC-direct” onset voltage. The area of the “hysteresis window” increases with an increase of gas pressure.