Observation of Detonation Wave and Shock Wave Generated by Detonation of a Silver Azide Pellet

Significance of Topic

Observing detonation waves and shock waves with high temporal and spatial resolution is crucial for advancing both fundamental research and practical applications, ranging from explosion physics to medical procedures such as laser-induced lithotripsy.

Objectives and Study Overview

The main goal of this study was to demonstrate the capabilities of Shimadzu’s Hyper Vision HPV-X3 camera in capturing and analyzing the dynamics of detonation and shock wave propagation generated by laser-triggered silver azide pellets. Two distinct recording configurations were employed to cover both large-scale shock propagation and fine details near the detonation point.

Methodology and Instrumentation

A 1.5 mm diameter silver azide (AgN3) pellet was fixed to the end of an optical fiber and detonated by focused laser irradiation. Two imaging setups were used:

• Recording ① (Schlieren method): 1 Mfps frame rate, field of view ≈ 250 mm, Z-type configuration with concave mirrors and knife edge to visualize shock waves and their reflection from an aluminum alloy plate.
• Recording ② (Shadowgraph method): 20 Mfps frame rate, field of view ≈ 9 mm, capturing the near-pellet detonation wave and emergence of the shock front with sub-microsecond resolution.

Key components:

• Shimadzu Hyper Vision HPV-X3 high-speed camera (burst-type sensor, constant resolution at all speeds)
• High-power pulsed laser light source
• Concave mirrors, knife edge assembly for Schlieren imaging
• Optical fiber mount for pellet positioning

Main Results and Discussion

Recording ① produced a time series (15 µs intervals) showing pellet detonation, shock wave expansion, reflection at the alloy plate, and subsequent interactions of reflected and primary shock fronts. Enlarged frames revealed ejected pellet fragments and a gradual increase in shock wave opening angle, highlighting the benefit of enhanced resolution.

Recording ② captured the initial detonation wave just 450 ns after laser firing, followed by shock wave formation beyond the detonation front. Frames up to 950 ns documented simultaneous expansion of both phenomena, resolving fine structural features of the wave fronts and ejected materials.

Benefits and Practical Applications

The HPV-X3’s unprecedented 20 Mfps capability and threefold improved resolution allow detailed visualization of ultra-fast explosive events. This is invaluable for:

• Fundamental studies in detonation physics and shock wave mechanics
• Safety testing and materials response analysis
• Medical research into laser-induced stone fragmentation mechanisms

Future Trends and Potential Applications

Ongoing sensor and data handling innovations are likely to push frame rates higher and expand dynamic range. Coupling high-speed imaging with real-time computational analysis and machine learning could enable automated tracking of wave fronts and fragments. The technology may extend to microscale explosion studies, multiphase flow imaging, and in-situ diagnostics in harsh environments.

Conclusion

Shimadzu’s Hyper Vision HPV-X3 high-speed camera significantly advances the observation of detonation and shock wave phenomena, combining extreme frame rates with high resolution. Its capabilities position it as a powerful tool across research, industrial testing, and biomedical applications.