Fig. 1. Branching structure of streamer discharges in synthetic air (the air pressure is 100 mbar; 16 cm point-plane gap, pulse voltage amplitude 10 kV)^[12]. 合成空气中流注放电分支图像(气压100 mbar (1 bar = 10⁵ Pa), 16 cm尖-板间隙, 脉冲电压幅值为10 kV)^[12]

Fig. 2. Schematic diagram of electrode arrangement.间隙布置示意图

Fig. 3. Three-dimensional simulation results of electron density at t = 9 ns for different nitrogen-oxygen ratio: (a) 80% : 20%; (b) 99% : 1%; (c) 1% : 99%. 不同氮气-氧气比例下流注电子密度三维仿真结果(t = 9 ns)　(a) 80% : 20%; (b) 99% : 1%; (c) 1% : 99%

Fig. 4. Electron density and electric field in simulated region at different moments. It shows the comparison of streamer branching results for different nitrogen-oxygen ratio: (a) 80% : 20%; (b) 99% : 1%; (c) 1% : 99%.不同氮气-氧气比例下流注发展仿真结果对比　(a) 80% : 20%; (b) 99% : 1%; (c) 1% : 99%

Fig. 5. Electron density and electric field in simulated region at different moments. It shows the comparison of streamerbranching results for different absorption cross sections: (a) χ_min = 0.0035 Torr^–1·cm^–1; (b) χ_min = 0.7 Torr^–1·cm^–1. 不同氧气吸收光子电离截面下流注发展　(a) χ_min = 0.0035 Torr^–1·cm^–1; (b) χ_min = 0.7 Torr^–1·cm^–1

Fig. 6. Photoionization efficiency coefficient as a function of reduced electric field.光电离效率系数关于约化场强的取值

Fig. 7. Electron density and electric field in simulated region at different moments. It shows the comparison of streamer branching results for different photoionization efficiency coefficient: (a) 2 ; (b) 0.1 . 不同光电离效率系数下流注发展仿真结果对比　(a) 2 ; (b) 0.1