Detonation (from Latin detonare 'to thunder down/forth') is a type of combustion involving a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. Detonations occur in both conventional solid and liquid explosives, as well as in reactive gases. The velocity of detonation in solid and liquid explosives is much higher than that in gaseous ones, which allows the wave system to be observed with greater detail (higher resolution).
A very wide variety of fuels may occur as gases, droplet fogs, or dust suspensions. Oxidants include halogens, ozone, hydrogen peroxide and oxides of nitrogen. Gaseous detonations are often associated with a mixture of fuel and oxidant in a composition somewhat below conventional flammability ratios. They happen most often in confined systems, but they sometimes occur in large vapor clouds. Other materials, such as acetylene, ozone, and hydrogen peroxide are detonable in the absence of dioxygen.Detonation was discovered in 1881 by two pairs of French scientists Marcellin Berthelot and P. Vieille and Ernest-François Mallard and Henry Louis Le Chatelier. The mathematical predictions of propagation were carried out first by David Chapman in 1899 and by Émile Jouguet in 1905, 1906 and 1917. The next advance in understanding detonation was made by Zel'dovich, von Neumann, and W. Doering in the early 1940s.