Comparative study of atmospheric pressure LF and RF micro jet plasmas produced in a single electrode system

Summary form only given. Non-thermal atmospheric pressure micro jet plasmas were generated in a single electrode system using either LF (several tens of kHz) or RF (13.56 MHz) power sources, and the characteristics of the produced plasmas were compared. A copper electrode with radius of about 360 mum was placed in a glass tube with radius of 3 mm, and the main gas was helium. The plasma characteristics, such as physical appearance, electrical properties, and temperature, were measured by various means. The LF plasma shown to be about 50 mm long on the average, and its temperature, measured using a thermocouple, was about the room temperature. When the helium flow rate was 3 l/min, the breakdown voltage was less than 1000 V. Also, the plasma was maintained with up to 1 % of oxygen gas mixed. On the other hand, the RF plasma was about 5 mm long at the most, but it was thicker in radius than the LF plasma. The measured rotational temperature was between 300 K and 380 K, which was higher than the LF plasma temperature. The emission spectrum was more intense with a larger number of He I lines. Both plasmas exhibited different characteristics, and a further study would define their advantages and disadvantages and thus match appropriate applications for each.