The accelerating development of atmospheric hypersonic vehicles and the increasing utilization of orbital space—both environments in which very high velocity particle impacts are effectively guaranteed to occur—has only deepened the need for accurate mechanical understanding of the highly coupled multi-physical phenomena observed in hypervelocity impacts. However, these highly transient early time impact phenomena are difficult to observe experimentally, and there is often a gap left in our experimental understanding of impact physics between the initial impact shock and the crater development process experienced by an impacted surface. Common to any sufficiently high velocity impact, however, is an intense burst of optical emission resulting from the vaporization and ionization of impact materials—usually called an impact flash—which provides a remotely and easily visible indirect signature of the earliest and most energetic mechanisms at play during the initial stages of impact and projectile penetration. While the impact flash can obscure experimental observation in impact experiments, the characteristics of the radiating materials generating the flash provide information about otherwise spatially and temporally unresolvable phenomena, such as impact jetting. This work performs experiments simultaneously imaging and observing the emission characteristics of the impact flash and the structure of the solid ejecta cone produced by high velocity normal and oblique impacts in reciprocal projectile/target configurations—where projectile and target materials are switched—in order to evaluate the early phase mechanisms of mixed-phase material ejection and their relationship to later stage solid material ejection responsible for the full scale development of the impact crater and ejecta cone familiar to impact experiments.
2022-04-06 08:00:00
