Detonation

Detonation is a rapid exothermic chemical reaction that propagates through a material by a self-sustained shock wave. The reaction front moves at supersonic speed and compresses and heats the material ahead, causing rapid decomposition and gas generation, typically at high pressures. Detonation contrasts with deflagration, where combustion proceeds as a subsonic flame front driven by heat transfer.

In energetic materials, detonation is initiated by a high-energy source or impact, and travels as a composite of a leading shock wave and a reaction zone. The speed of detonation, known as detonation velocity, depends on material and confinement; for common explosives it ranges roughly from 1.5 to 9 km/s. The Chapman-Jouguet theory provides a model for steady detonation fronts; real materials show variability and may be under- or overdriven.

Confinement and density influence initiation and propagation; poor confinement may fail to sustain detonation. Detonation produces high-pressure, high-temperature gases and solid residues; the products expand rapidly, producing a blast wave and destructive effects.

Applications include mining and quarrying, construction demolition, military ordnance, and experimental propulsion concepts such as detonation-based engines and pulse detonation engines. Safety considerations include handling sensitive materials, appropriate initiation systems, and containment to control energy release and reduce unintended detonation.