Recent progress in research on the dynamic process of high-energy explosives through pump-probe experiments at high-intensity laser facilities

Abstract

To accurately predict the detonation and safety performances of high-energy explosives, it is necessary to investigate their reaction mechanisms on different scales, which, however, presents a challenge due to the complex reaction kinetics of the explosives and a lack of experimental methods presently. This work introduces the time-resolved pump-probe experiments capabilities aiming at high-energy explosives based on large-scale laser facilities and presents the recent progress in research on the dynamic process of the explosives, obtaining the following understandings: (1) First, the micron-sized single-crystal 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) can be compressed to an overdriven detonation state at a laser facility, followed by the shock Hugoniot measurements of TATB; (2) Second, high resolution transient X-ray radiography makes it possible to achieve the dynamic imaging of the internal deformation, damage, and reaction dynamics of high-energy explosive under dynamic loading; (3) Third, the phase transformation and chemical reaction products of the shock-compressed explosives can be investigated using dynamic X-ray diffraction or scattering spectra; (4) Finally, the structural changes, molecular reactions, molecular bond cleavage, and intermediate product components of explosives under ultrafast pumping can be explored using ultrafast laser spectroscopy. Large-scale laser facilities can provide various flexible pump-probe methods, including laser shock loading, transient X-ray imaging, dynamic X-ray diffraction, and ultrafast spectroscopy, allowing a series of experiments to be carried out to evaluate different levels of ignitions from low-pressure to overdriven detonations. Furthermore, the facilities also enable in situ, real-time investigations of the internal deformation, phase transition, and ultrafast dynamics of explosives under dynamic loading at high spatial and temporal resolutions. The study of the reaction kinetics and mechanisms of high-energy explosives on microscopic-mesoscopic scales provides an efficient means to unravel the mystery of explosive reactions.