Pulse Parameter Dependence of Reactive Species Generation in Global simulation of Atmospheric Argon/Oxygen Plasma.

Abstract

A global simulation of atmospheric Argon/Oxygen plasma was performed to investigate the dependence of reactive species density on microwave pulse power parameters. The time-averaged densities of reactive species are affected by pulse period and duty. Varying pulse period would change the duration of high electron temperature. The duty determines the instantaneous power density and higher instantaneous power resulted in higher electron temperature. This dependency of electron temperature are explained by electron valance equation. A more realistic global simulation was carried out in consideration of the change of the plasma impedance within each pulse period, which affects the power coupling efficiency. An empirical model for the impedance of plasma jet and the observed evolution of the plasma length are used to apply the time-varying power coupling to the global simulation. The pulse operation reduces the impedance mismatch between the plasma and the electrode, resulting in higher energy transfer efficiency compared to the case of continuous wave. This advantage of pulse operation is expected to be applicable to many resonator type plasma devices.