Sensing Plasma Jet Electromagnetic Signals

The paper discusses the sensing and evaluation of signals obtained in the radio wave region within a plasma channel (plasma stream) at the generator frequency $f=13.56$ MHz. The main focus is on the plasma discharge at an atmospheric pressure. The experimental measurements are accompanied by an analysis of the numerical model. Diverse variants of plasma channel models formed in a glass capillary chamber were considered. The analyses reflected the impact of the location of the sensing elements, such as antennas and sensors, on the resulting sensed electromagnetic signal. The methodology thus conceived is significant in radio-frequency evaluation of plasma parameters in both simple capillary jets and more complex plasma chambers, namely, cryo-chambers with a slit-like structure.