Initiation of PETN high explosive by pulse laser-induced high-temperature plasma

Nano-second infrared laser pulse was used to initiate PETN powder. Goal of this study is to develop a laser-driven method of initiating a secondary high explosive charge, based on the energy conversion from the pulsed laser energy to the shock wave energy. We found that enhanced energy conversion was evidenced from optical to mechanical by an intentionally roughened surface of a transparent medium through which laser beam propagates. Thin aluminum coating of less than 1 mm has been made to further enhance the laser absorption by the surface. Produced air shock waves from the PMMA plate with roughened surface was observed by the laser shadowgraphy technique. Emission by the detonation of PETN powder was recorded by an image converter streak camera. Although the thickness of the explosive is very thin (0.5 mm), a slight delay in the initiation was shown. Initiation tests with varying the roughness of the surface, laser energy, laser fluence were performed to study the process.