Experimental Characterization of Atmospheric-Pressure Plasma Using Langmuir Probe Techniques

Langmuir probe diagnosis of a Cold Atmospheric Plasma (CAP) jet requires inserting the probe directly into the downstream zone, which causes extra filament discharges and thereby changes the plasma properties. In this work, we present a technique to sample the CAP jet into a low pressure chamber via an aperture for Langmuir probe diagnosis. Since the extracted sample carries very low current, multiple probe designs have been tested to get a proper I-V curve. The Langmuir probe theory for collisional plasmas was used, which is based on bulk flow velocity and sheath thickness. The plasma density and temperature are estimated to be. × / and 3.1 eV respectively, for the operating condition of 1W at 12 kHz, with very low argon flow rate.