1032 レーザー誘起水中集束衝撃波の圧力波形に及ぼすレーザー強度分布の影響(S04-3 実験力学における計測・解析法の新展開(3)高速・衝撃現象,21世紀地球環境革命の機械工学:人・マイクロナノ・エネルギー・環境)

抄録

A concave cylindrical surface of solid is irradiated by pulsed laser beams in water. The laser irradiation generates cylindrical underwater shock waves that propagate and converge at the axis of the cylinder. The pressure waveforms of the shock waves are measured at the focal point, where the shock wave consists of a positive pressure pulse and a negative one that follows the positive pressure pulse. The pressure waveforms are measured with varying the intensity distribution of the laser beam on the cylindrical surface. Three kinds of intensity distribution are used, that are uniform, Gaussian and two tops distribution. The measurement results show that the ratio of the negative peak pressure to the positive one is about 0.55, and does not change much even though the intensity distribution of laser beam varies.