Characteristics of Cold Plasma Jet Initiated by Non-Contact and Contact Pulse Voltage

In the paper, the characteristics of a cold atmospheric plasma jet generated by non-contact and contact methods of initiating a gas discharge with a pulsed voltage are investigated. The parameters of current detectabled in the contact zone of the plasma jet touching the object, depending on the amplitude and duration of unipolar positive pulses for contact and non-contact initiation of the discharge, have been studied. The frequency of touching of the plasma jet current with the object under different durations of initiating voltage pulses and pulse repetition frequencies has been investigated. The spectral analysis of the plasma jet interaction zone with object has been carried out. The modes providing the highest intensity of OH radical emission were determined. The temperature increment in the cold plasma jet interaction zone with the object at different parameters of voltage and speed of gas pumped through the device has been investigated. Comparative research of the characteristics of cold plasma jets initiated by contact and non-contact excitation by unipolar positive pulses has been carried out. It is established that the amplitude of the current registered on the object surface is several times higher for the plasma jet initiated by contact excitation of the gas medium. It is shown that at non-contact method of discharge ignition by unipolar positive pulses the frequency of current touching the object of influence matches with the repetition frequency of voltage pulses.