Experimental investigation of optical and electrical properties of various explosive fireballs

Acquiring quantitative experimental data of explosive fireballs at early time scales is crucial for validating 1-D numerical models of spherical charges. While numerical modeling remains a powerful tool for elucidating explosive phenomena, such predictions still require some degree of physical validation from experiments. Currently, much interest surrounds how properties vary near the shock wave front. Upon detonation, the shock wave propagates outward with detonation products traveling closely behind. Much has been studied regarding the pressure from the incident shock wave; however, little is known about the electrical and optical properties of the subsequent detonation products behind this shock wave in the first few hundred microseconds following detonation. It is the temporal relationship between these two regions, as well as the optical and electrical properties of the fireball, that are of interest in this study. The specific properties that are examined in this work include temperature, UV-visible spectra, electrical conductivity, magnetic field strength, blast pressure, residue, and radio frequency generation. Explosives such as TNT, RDX, HMX, Comp B, Tritonal, and Nitromethane were utilized to assess the effects of varied carbon content on each of the aforementioned properties. Furthermore, the ambient pressure was manipulated to alter kinetics and simulate blast scaling effects. Lastly, the ambient environment was varied between air and an inert gas (nitrogen) to limit the amount of available oxygen, thus adjusting the overall carbon content and kinetics