Discoveries in detonation of molecular condensed explosives in the 20th Century

A number of experimental results that could not be satisfactorily explained within the framework of the Grib–Zel'dovich–Neumann–Döring detonation theory are reviewed, namely, the oscillating detonation of some liquid high explosives (HE), the weak dependence of the time of detonation transformation of heterogeneous charges on their structure (particle size, liquid or solid state, etc.) with a strong dependence of the critical diameter of detonation on the structure, and the extremely weak dependence of the detonation rate of liquid HE on the charge diameter with a significant value of the critical diameter of detonation. These studies yielded the following results: 1) for each heterogeneous HE, a typical shock–wave pressure $p^*$ and a typical initial density $\rho_0^*$ were found, such that, for their low values, HE transformation follows the mechanism of hot points (depends on the charge structure), and for high values of these parameters, HE transformation obeys the homogeneous mechanism (does not depend on the charge structure); 2) two new theoretical notions were discovered and used in the detonation theory: the phenomenon of breakdown of the chemical reaction in the shock–wave front by rarefaction waves and the notion of a “shock jump”, which reflects the specific character of action of shock waves on complex multiatomic molecules of condensed HE. It was also shown that the discovery of the parameters $p^*$ and $\rho_0^*$ and the breakdown and “shock jump” phenomena allowed one to confirm experimentally the explanations of the above observations, which are incompatible with the Grib–Zel'dovich–Neumann–Döring detonation theory, to propose the structure of the front of detonation waves both in homogeneous (stable and oscillating) and heterogeneous HE whose basic property is HE transformation (partial or complete depending on the HE power and initial density) already in the shock–wave front, and to proposed principally new ideas on the nature of the critical diameter of detonation of homogeneous and heterogeneous HE.