Optical Study Of Diffuse Bi-directional Nanosecond Pulsed Dielectric Barrier Discharge In Nitrogen At Atmospheric Pressure

In this study, a bi-directional high voltage pulse with 20 ns rising time is employed to generate diffuse glow-like dielectric barrier discharge plasma with very low gas temperature in N2 using needle-plate electrode configuration at atmospheric pressure. The discharge diffuse performance, the gas temperature, and the optical emission spectra of the discharge are investigated. The main results presented in the dissertation have been summarized as follows:1. The diffuse glow-like nanosecond pulse dielectric barrier discharge plasma is presented in N2 with needle-plate electrode configuration at AP under severe electromagnetic interference. The effects of pulse peak voltage and pulse repetition rate on the emission intensities of NO (A2∑�'X2∏), OH (A2∑�'X2∏,0-0), N2 (C3∏u�'B3∏g,0-0,337.1 nm), and N2+(B2∑u+�'X2∑g+,0-0,391.4 nm) are investigated. It is found that the emission intensities of NO (A2∑�'X2∏), OH (A2∑�'X2∏,0-0), N2 (C3∏u�'B3∏g,0-0,337.1 nm), and N2+(B2∑u+�'X2∑g+,0-0,391.4 nm) rise with increasing pulse peak voltage and pulse repetition rate. The gas temperature of the plasma is determined by measuring the optical emission spectra of the first negative band of N2+(B2∑u+�'X2∑g+,0-0,391.4 nm). It is found that the gas temperature rises gradually with pulse peak voltage and pulse repetition rate.2. The effects of adding Ar and O2 to N2 on the discharge diffuse performance and the emission intensities of NO (A2∑�'X2∏), OH (A2∑�'X2∏,0-0), N2 (C3∏u�'B3∏g,0-0, 337.1 nm), and N2+(B2∑U+�'X2∑g+,0-0,391.4 nm) are investigated. When the concentration of Ar increases, the discharge gets more intense, the discharge volume is enlarged in both radial and horizontal directions, and the emission intensities of NO (A2∑�'X2∏), OH (A2∑�'X2∏,0-0), N2 (C3∏u�'B3∏g,0-0,337.1 nm), and N2+(B2∑U+�'X2∑g+,0-0,391.4 nm) rise with the increasing of the concentration of Ar. However, the addition of O2 is not conductive to improve the diffuse performance of the discharge. The discharge gets weak and the discharge volume constricts in both radial and horizontal directions, the emission intensities of NO (A2∑�'X2∏), OH (A2∑�'X2∏,0-0), N2(C3∏u�'B3∏g,0-0,337.1 nm), and N2+ (B2∑U+�'X2∑g+,0-0,391.4 nm) decrease with the rising of the concentration of O2.