Detonation vs Deflagration

Chapman-Jouguet detonation (1899–1905): a self-sustaining supersonic combustion wave. Structure: lead shock compresses and heats the unreacted fuel to ignition, then chemical reaction completes at the CJ plane. Wave speed D_CJ = √[2(γ²-1)Q] for ideal gas. Products travel at exactly sonic speed relative to the wave (M=1 at CJ plane). Unlike deflagration (subsonic, pressure-driven), detonations cannot be stopped by removing the ignition source.