Detonation
Detonation is a type of combustion which involves a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. The rate at which detonation occurs, is higher than the sonic velocity in the medium. Detonation propagates through shock waves, supersonically with speeds in the range of 1 km/sec, and thereby, differ from deflagration which propagate with subsonic flame. speeds in the range of 1 m/sec. Detonation takes place, in both conventional solid and liquid explosives, as well as in reactive gases. The solution of any steady state deflagration and detonation waves lies on the Hugoniot curve, which can be divided into several branches and regimes, corresponding to the different types of combustion waves (detonation or deflagration).
The region 1 is strong detonation, the gas velocity relative to the wave front is slowed down substantially from supersonic speed to subsonic.
The region 2 represents a weak detonation as the gas velocity in relation to the wave front is slowed down substantially from supersonic speed to subsonic.
The region 3 is weak deflagration, gas velocity relative to the wave Font is accelerated from a subsonic velocity to a higher subsonic velocity.
The region 4 represents strong deflagration, as gas velocity relative to the wave front is accelerated from subsonic to supersonic substantially
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Detonation was discovered in 1881 by four French scientists Marcellin Berthelot and Paul Marie Eugène Vieille and Ernest-François Mallard and Henry Louis Le Chatelier. The next advance in understanding detonation was made by John von Neumann and Werner Döring in the early 1940s and Yakov B. Zel'dovich and Aleksandr Solomonovich Kompaneets in the 1960s.
.Davis, W. C. (1987). The detonation of explosives. Scientific American, 256(5), 106-113. https://engrxiv.org/preprint/view/3246/5877