表面放电等离子体产生冲击波特性

Investigation on properties of surface discharge plasma induced shockwave

采用压力传感器,分析XeF(C→A)激光器高电压表面放电光泵浦方式不同位置、不同放电电压条件下冲击波特性。研究结果表明,表面放电等离子体膨胀产生的冲击波持续时间为ms量级,在冲击波过后伴随有相对较弱的压力波。随着充电电压增加,放电过程释放能量增多,冲击波峰值压强也变大,最大压强可达1 MPa,同时冲击波峰值延后,冲击波持续时间变长。

The XeF（C→A） laser has many potential applications in laser underwater detecting due to the fact that its wave- length located in 450~520 nm band is the best propagating window in atmosphere and sea. The technique of surface discharge op- tical pumping possesses many advantages, such as intense violet and vacuum-violet radiation, relatively low charge voltage, non- essential high current switch, high temperature and high repetition rate, and easy realization in technique. Therefore it becomes a highly efficient pumping for Xe（C→A） laser. Intense shockwave is generated during the expansion of plasma induced by surface discharge. The intense shockwave results in the turbulence of homogeneity and refractive index of active medium, and impacts on the output of XeF laser consequently. Therefore, it is important to study the properties of generation and propagation of the shockwave. By employing a pressure sensor, properties of the shockwave measured at various spots and discharge voltages are an- alyzed. The results indicate that the duration of the shockwave, followed by a relatively weaker pressure wave, is in the ms range. The higher the charge voltage and the more the released energy, the higher the peak pressure of the shockwave with the maximum pressure of up to 1 MPa, the more the peak position delayed, and the longer the duration. The research points out a di- rection for improving the output stability of XeF（C-＊A） laser at relatively high repetition rate.