Effect of target material on electrical properties of a two-electrode dielectric barrier helium plasma jet

In this paper we present electrical characterization of a dielectric barrier discharge (DBD) plasma jet operating with He (2 slm and 3 slm) as working gas and interacting with Cu, PET and distilled H2O targets. We used a plasma jet with two copper electrodes wrapped around a glass tube. One electrode was powered by a high-voltage sinusoidal signal of 30 kHz, whereas the other electrode and the target holder were grounded. We have performed detailed investigation of the voltage and current waveforms, phase differences, volt-current (V-I) characteristics, calculated impedances and power deposition. The aim was to determine the influence of different target materials and their conductivity on the plasma properties. We calculated the total harmonic distortion (THD) factor that showed that the current through grounded electrode depends on the conductivity of the target. We also calculated the power delivered to the plasma core and the plasma plume regions and observed that the change in the target conductance influenced the power in both plasma regions. The experimentally characterized electrical circuit was simulated by a model of equivalent electrical circuit corresponding to the plasma-off and plasma-on regime. Voltage controlled current source was added as model of a streamer formed in plasma-on regime.