Energy transfer and reactive species generation in atmospheric pressure Argon plasma driven by microwave pulse

Abstract

Atmospheric argon plasma experiments with pulsed microwaves were performed. Immediately after the pulse on, the electron temperature rapidly increases because relatively high power can be delivered to the low-density electrons. The increased electron temperature enhances the electron impact ionization or excitation and these reactions consume the kinetic energy of the electrons. Rapid increase and decrease of atomic, molecular, and continuum emissions are observed due to strong dependence of the emissions on the electron temperature. The electron collision reaction converts the energy of the electron into the chemical energy of the reactive species during the pulse on time. Because many of the reactive species have relatively long lifetime, they serve a role of energy storage. The stored chemical energy in the reactive species is then released at the pulse off time to the effect that the decline of electron density is delayed, thereby facilitating the discharge at the next pulse by maintaining a sufficient density of seed electrons. Global simulations based on the above scenarios will be presented.