Detonaatio

Detonation, or detonaatio in some languages, is the rapid propagation of a chemical reaction through an explosive material, driven by a shock wave. The reaction front travels at a detonation velocity, typically several kilometers per second, and far exceeds the material’s speed of sound. As the front passes, the energy release raises pressure and temperature dramatically, producing a high-pressure, high-temperature mixture of hot gases.

Mechanism and characteristics: A detonation consists of a leading shock wave followed by a narrow reaction zone where the explosive decomposes. The process is highly exothermic and produces high-velocity products. The detonation velocity and the composition of the products depend on the material, its density and confinement. The Chapman–Jouguet (CJ) condition describes a steady detonation in which the detonation products exit the reaction zone at sonic speed relative to the front.

Comparison to deflagration: Detonation is distinguished from deflagration, a slower, subsonic combustion wave driven by heat transfer rather than a shock. In practice, many explosives are designed to achieve detonation, while improper confinement or contamination can cause deflagration or unintended transitions from deflagration to detonation (the DDT phenomenon).

Applications and safety: Detonation is central to the use of explosives in mining, construction, demolition, and military contexts. It is controlled via standardized safety protocols, containment, and regulatory oversight. Because detonation generates extreme pressures and temperatures, it poses significant safety and environmental risks and is subject to strict regulations.