452 / 2017-05-03 09:08:22

Enhancement and Modulation of Plasma Parameters in Dual Radio-frequency Dielectric Barrier Discharge Via Nonlinear Coupling Effect

13833,13834,13835

Precise independent control of plasma parameters in dual frequency atmospheric pressure discharges have solicited rampant interest from numerous groups in recent years due to the myriad of potential applications if harnessed effectively. Previous theoretical work on dual frequency radio-frequency (RF) discharges reveal possibility for enhancement of electron densitiy with independent control of gas temperatures through the nonlinear coupling effect. However the intrinsic physical mechanism and interactions underlying the discharge is still unclear. In this work, a semi-kinetic one-dimensional fluid model has been constructed to investigate the enhancement of plasma parameters as a function of modulated discharge parameters in a dual frequency atmospheric dielectric barrier discharge driven by dual frequency RF excitations. Results show that the average electron energy and electron density are inversely related as a function of applied power density. As the phase difference between the RF signals shifts from 0 to 2π, the average electron energy first increases before decreasing. Henceforth, fine tuning of the power density and phase difference enables the independent control over electron energy and electron density. This can be exploited to directly manipulate both the phase dependent and time averaged effective electron energy distribution function. Fast Fourier transform (FFT) analysis of the discharge current density when a a good coupling between the dual frequencies have been achieved also shows the presence of contributions from several higher harmonics from the FFT spectra.