纳秒脉冲等离子体放电特性研究

Study on Discharge Characteristics of Nanosecond Pulsed Plasma

在定容弹内,试验研究了空气压力、脉冲重复频率和电极结构对等离子体放电的影响.结果表明,等离子体放电会诱导冲击波的产生;空气压力越高时,脉冲放电能量越高,放电电弧越明亮,冲击波传播速度也越快,放电产生的粒子云团面积越大.但在高空气压力下,粒子云团扩散速率降低.纳秒脉冲放电频率影响脉冲放电电压大小.随着脉冲放电频率的增加,脉冲最大放电电压下降.在圆柱形火花塞下,脉冲重复频率越高时,连续脉冲的最大放电电压越小,脉冲放电区移动范围减小,同一时刻下粒子云团扩散面积增大.与圆柱形火花塞相比,圆锥形火花塞间隙内放电区域电场结构与分布发生显著变化,空间电荷密度增加,击穿电压升高,相同时刻下粒子云团扩散范围增大.

The effects of air pressure,pulse repetition frequency and electrode structures on plasma discharge were investigated experimentally in a constant-volume chamber.Results show that plasma discharge can induce the generation of shock waves.A higher air pressure led to a higher pulse discharge energy and a brighter discharge arc.Furthermore,the shock wave traveled faster and the area of particles from the discharge was larger.However,the diffusion rate of the particle cloud decreased under high air pressure.The discharge frequency of nanosecond pulses affected the pulsed discharge voltage.With the increase in pulse repetition frequency,the maximum pulsed dis-charge voltage decreased.In the case of a cylindrical spark plug,the maximum discharge voltage in the conditions of continuous pulses decreased and the movement range of the pulsed discharge region decreased with the increas-ing pulse repetition frequency.At the same time,a larger diffusion area of the particle cloud was formed.Com-pared with those in the case of the cylindrical spark plug,the electric field structures and distributions of the dis-charge from the conical spark plug changed significantly,leading to an increasing space charge density and a higher breakdown voltage.In addition,the particle cloud distributed more widely at the same time.