Discharge Behaviors of SCN2 at the Temperature 127K and Pressure 4 MPa Under DC Voltage

The precise mathematical method was adopted to simulation the breakdown process of the 5mm gap of the rod-plate electrode system being filled supercritical nitrogen at the condition of 127K, 4MPa and seed electron density1 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\times 10^{6}\mathrm{m}^{-3}$</tex> under 29kV DC voltage. The results showed that the discharge process was completed in 11.8 ns from seed electron triggering, avalanche bulking to streamer extending until gap eventually breakdown. The entire gap breakdown process was divided into three discharge stages, namely, the initial discharge triggered in <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0\sim 4\text{ns}, 4\text{ns}\sim 7\text{ns}$</tex> avalanche and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$7\text{ns}\sim 11.8\text{ns}$</tex> streamer phase. At the same time, the facts were also revealed that the discharge evolution, electric field distribution, and electron density had different values, and also showed different temporal and spatial distribution characteristics along the axis of discharge gap. The research results obtained in this paper could be helpful to understand the discharge mechanism of supercritical nitrogen and provide theoretical basis for its application.