Direct initiation of gaseous detonation: the Jungle

A general assessment of the state of the art regarding direct initiation modes for successful cylindrical or spherical detonations in uniform gaseous media is presented. Energy is recognized as being the most appropriate parameter to be used as a relative measure of the sensitivity to detonation of any given explosive mixture. A spherical detonation wave can be initiated either by a point source or a confined planar detonation wave transmission at the open end of a tube into an unconfined environment. Consequently, the critical conditions characterizing the amount of initial energy required to create the detonation are, respectively, the initiation radius for a point source and the critical tube diameter for a diffraction. The description of the phenomenology of critical conditions for gaseous detonation is proposed through notions having been diversely expressed by different authors. Nevertheless, these notions differ as far as their formulation and their analysis of the concepts proposed is concerned. It's a real jungle !. So, this is why it is important to provide some information on the current state of the art regarding the initiation modes for cylindrical or spherical detonations.