›› 2014, Vol. 23 ›› Issue (8): 85203-085203.doi: 10.1088/1674-1056/23/8/085203
• PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES • 上一篇 下一篇
刘天航, 郝作强, 高勋, 刘泽昊, 林景全
Liu Tian-Hang (刘天航), Hao Zuo-Qiang (郝作强), Gao Xun (高勋), Liu Ze-Hao (刘泽昊), Lin Jing-Quan (林景全)
摘要: The propagation of a plasma shock wave generated from an Al target surface ablated by a nanosecond Nd:YAG laser operating at 355 nm in air is investigated at the different focusing positions of the laser beam by using a time-resolved shadowgraph imaging technique. The results show that in the case of a target surface set at the off-focus position, the condition of the focal point behind or in front of the target surface greatly influences the evolution of an Al plasma shock wave, and an ionization channel forms in the case of the focal point set in front of the target surface. Moreover, it is found that the shadowgraph with the evolution time around 100 ns shows that a protrusion appears at the front tip of the shock wave if the focal point is at the target surface. In addition, the calculated results of the expanding velocity of the shock wave front, the mass density, and pressure just behind the shock wave front are presented based on the shadowgraphs.
中图分类号: (Shock waves and discontinuities)