Experimental characterization of TIAGO torch discharges: surface wave discharge behavior and (post-)discharge kinetics

Abstract

The Torche à Injection Axial sur Guide d’Ondes source -better-known as TIAGO torch- is a particular type of Microwave Induced Plasma which has become in the technological and scientific spotlight due to its outstanding features. Moreover, TIAGO torch device arouses interest thanks to its remarkable performance in many challenging topics as green energy generation or graphene production by hydrocarbons decomposition. Although it has not been experimentally demonstrated up to date, discharges generated by a TIAGO torch have been theoretically predicted to be Surface Wave Discharges, a kind of plasmas leading the development of new materials. Therefore, a deeper and fundamental research of this device is needed to optimize the implementation of plasma technology to these fields. In this study, the axial distribution of gas temperature, electron density and intensity of main atomic and molecular emissions have been studied by Optical Emission Spectroscopy feeding the discharge with different input power values (200, 400 and 600 W). A complete axial characterization of both the dart and the plume regions is depicted and, according to the data obtained for the main plasma parameters, different regions can be identified, being the radiation zone reported for the first time at atmospheric pressure. The kinetics of both the dart and the plume are discussed and an experimental verification of the TIAGO torch behavior as a surface wave discharge is presented for first time.