Numerical investigation of the directional control of electron density and gas temperature in atmospheric pressure dielectric barrier discharge by using low- and high-frequency coupling modulation

Abstract

Dielectric barrier discharges (DBDs) are commonly used as efficient sources of large volume diffuse plasmas with moderate temperature and plenty of reactive particles, but the synergistic linkage of some key plasma parameters in single frequency driven systems sometimes limits their application fields and accessible operating ranges. The discrete control of certain key plasma parameters by multi-frequency, i.e., dual frequency (DF), voltage waveform excitations is of increasing requirement and importance for both application-focused and fundamental studies on DBD plasma. In this paper, a significant nonlinear coupling modulation of the discharge evolution process and characteristics caused by the HF oscillation of the high-frequency component in the DF DBD system is observed and investigated, which provides a simple and efficient approach to realize the independent control of the target key plasma parameters such as gas temperature and electron density. Based on a one-dimensional fluid model with semi-kinetics treatment, numerical studies of the tiny high frequency component on the properties modulation of atmospheric DF DBD are reported. The driving voltage waveform is characterized by a 50 kHz fundamental sinusoidal low-frequency signal superimposing a small amount of 2 MHz high-frequency signal [HF component changing from 0 to 100 V with a low-frequency (LF) component fixed at 1 kV as a constant], and the effects of the high-frequency voltage amplitude and phase shift on the discharge characteristics, sheath dynamics, impact ionization of electrons, and key plasma parameters are investigated. Particularly, the effects of phase modulation on the discharge evolution and characteristics for DF DBDs are discussed and revealed. The results have demonstrated that a slight and proper parameter variation of the high-frequency oscillation can provide a high electron seed density, and trap electrons within the sheath, thus achieving required plasma parameters. The sheath dynamics can be effectively modulated by tuning the phase shift, which enables a possible alternative approach to optimize the independent control of the key plasma parameters under atmospheric pressure.

Reduced electric field and gas temperature effects on chemical product dynamics in air surface dielectric barrier discharges: from macro-physical parameters to micro-chemical mechanisms

“…BOLSIG+ is a computer program that is widely used to numerically solve the Boltzmann equation for electrons in various types of gas discharges and collisional low-temperature plasmas. [46][47][48][49] By setting parameters such as gas components, collision cross-section and measured reduced electric field, the program can directly output the results of the electron energy distribution function, which allows to calculate the corresponding mean electron energy according to eqn (4), where e denotes the mean electron energy, f 0 denotes the EEDF, and e is the electron energy.…”

Compensation of Heat Effect in Dielectric Barrier Discharge (DBD) Plasma System for Radar Cross-Section (RCS) Reduction

“…The dielectric barrier discharge (DBD) plasma generator, on the other hand, is relatively thin and generates less heat during plasma generation compared to inductively coupled plasma (ICP) [ 18 , 19 , 20 , 21 ]. However, the DBD plasma generator structure also requires the application of a high bias voltage, which generates significant heat that, although small compared to ICP, can cause structural deformation depending on the thermal tolerance of the DBD plasma generator components.…”

Numerical Study of Ar/O2 Discharge Properties Influenced by Small Secondary Electron Emission in Dual-Frequency Atmospheric Pressure Discharge

“…They reported that a dualfrequency source could efficiently enhance the plasma characteristics of an atmosphericpressure dielectric barrier discharge and provided a possible approach to controlling and optimizing key plasma parameters and even enabled separate control of density and gas temperature. They also performed numerical studies on the directional control of electron density and gas temperature in the dielectric barrier discharge using dual frequencies [10]. D. B. Kim et al [11] conducted experimental studies on the atmospheric pressure discharge plasma driven by a dual-frequency source combining radio frequencies of 2 and 13.56 Mhz.…”