| AVS 55th International Symposium & Exhibition | |
| Plasma Science and Technology | Wednesday Sessions |
| Session PS2-WeA |
| Session: | Plasma Diagnostics, Sensors, and Control I |
| Presenter: | C.Y. Wu, National Taiwan University |
| Authors: | C.Y. Wu, National Taiwan University C.W. Chen, Industrial Technology Research Institute, Taiwan W.C. Cheng, Industrial Technology Research Institute, Taiwan C.C. Hsu, National Taiwan University |
| Correspondent: | Click to Email |
An arc plasma jet under atmospheric pressure was studied. This plasma jet is able to generate stable plasma sustained by a DC pulsed power of 20 kHz ~ 40 kHz using nitrogen and clean dry air. A voltage probe and a current probe were used to characterize the voltage and current waveform of this plasma jet. The optical emission at this plasma jet downstream was monitored by an optical emission spectrometer. Multiple thermocouples were used to measure the downstream jet temperature. The current and voltage waveforms showed glow-to-arc-transition-like characteristics. It is found that the time-averaged current increases with the power input and is not sensitive to the flow rate. The peak current, however, increases as the applied power decreases and as the flow rate increases. The peak current remains below 1.0 A under high power and low flow rate conditions while reaches 3.0 A for low power and high flow operation regimes. It suggests that the peak current is not directly controlled by the amount of power input to the plasma. Optical diagnostics shows nitrogen molecular emissions dominate in nitrogen plasma jets. The nitrogen plasma jet temperature appears to be higher than the temperature of the air plasma jet as measured by the thermocouples at the jet downstream. The detailed discharge mechanism will be presented and its implications in materials processing will be discussed.