The transit to detonation in high explosives

Accidents with explosive materials are still too common over 150 years after the patenting of dynamite. The manner by which they transit from burn to detonation (Deflagration to Detonation Transition; DDT) after a random thermal event, such as an electrical arc, or by friction if a package is dropped, is by far the single biggest risk associated with explosives storage and use. However this is a particularly difficult process to observe and quantify. Thus there are no agreed and verified theoretical frameworks for the process and thus no comprehensive predictive modelling capabilities. Recent experiments conducted at the Diamond Synchrotron have yielded ground-breaking, time-resolved observations of DDT. They have pioneered new experimental techniques and opened a new area for fast imaging at synchrotrons. We illustrate critical processes that occur within burning to detonation revealed in this study. These provide a new framework for understanding processes operating and offer the means to handle this class of materials more safely.