Ultra‐High Fidelity Laser‐Induced Air Shock from Energetic Materials

• Published in: Propellants, explosives, pyrotechnics Vol. 45; no. 3; pp. 396 - 405
• Main Authors: Biss, Matthew M., Brown, Kathryn E., Tilger, Christopher F.
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.03.2020; Wiley
• Subjects: Accuracy; air blast; detonation performance; energetic material characterization; energetic material performance; Energetic materials; Explosives; laser-induced plasma; laser-induced shock wave; Lasers; MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE; Pulsed lasers; shock physics; shock physics laser-induced plasma; Shock waves; Velocity; Velocity distribution
• ISSN: 0721-3115; 1521-4087
• DOI: 10.1002/prep.201900130

Recent interest in the implementation of the Laser‐induced Air Shock from Energetic Materials (LASEM) technique prompted an investigation using ultra‐high‐speed imaging diagnostics to provide early‐time (sub‐μs) shock‐wave‐radius‐versus‐time data necessary to accurately determine the characteristic laser‐induced‐shock velocity (y‐intercept) for high explosives (HE) of interest. Ultra‐high‐speed focused‐shadowgraphy images were collected from nanosecond‐pulsed laser‐ablated samples of HE similar to those in the published literature. Shadowgraphy images were collected using interframe times ranging from 50–750 ns, with exposure times of 5 ns. Acquired shock‐wave‐radius‐versus‐time data permitted a high‐fidelity assessment of the shock wave velocity produced at the characteristic radius of the generated laser‐plasma pulse. The resulting data from eight different HE indicated that early‐time energy contributions and the resulting laser‐induced shock velocity profiles produced from ablation of the HE material were indistinguishable amongst the explosives tested for the majority of the time domain characterized (0–12 μs).