A uniform glow discharge plasma source at atmospheric pressure

TLDR

An atmospheric‑pressure, uniform, continuous glow plasma was generated in ambient air with argon feed using a 13.56 MHz RF source, producing a 200 mm × 50 mm × 5 mm discharge that can be scaled to 600 mm length for large‑area applications. The discharge exhibited classic glow‑discharge behavior without streamers or arcs, with rotational temperatures of 490–630 K, vibrational temperatures of 2000–3300 K, and over 93 % uniformity along its length.

Abstract

An atmospheric-pressure, uniform, continuous, glow plasma was produced in ambient air assisted by argon feeding gas, using a 13.56 MHz rf source. Based on the measured current–voltage curve and optical emission spectrum intensity, the plasma showed typical glow discharge characteristics, free from streamers and arc. The measured rotational and vibrational temperatures were in the range of 490 to 630 K and 2000 to 3300 K, respectively, within the operation range of argon flow rate and rf power. From the spatial measurement of total optical emission intensity, and rotational and vibrational temperatures, the plasma shows very high uniformity (over 93%) in the lengthwise direction. The plasma size for this study was 200 mm×50 mm×5 mm, although a plasma was produced in the scaled-up version of 600 mm in length, aiming for large-area plasma applications.