F18 Super Hornet MACH/SHOCK Diamonds in flight (slow motion)

Video I filmed of an high speed F18 pass with afterburners on. Filmed at 12X zoom and at 600 FPS. Usually you can only see these in low light but the contrast of the sky in the background was just enough so we could see this interesting phenomenon.

Shock diamonds (also known as Mach diamonds, Mach disks or dancing diamonds) are a formation of stationary wave patterns that appears in the exhaust plume of an aerospace propulsion system, such as a supersonic jet engine, rocket, ramjet, or scramjet when it is operated in an atmosphere.

Shock diamonds are formed when the supersonic exhaust from a nozzle is slightly over or under-expanded, meaning that the pressure of the gases exiting the nozzle is different from the ambient air pressure. A complex flow field results as the shock wave is reflected back and forth between the free fluid jet boundary and a visible repeating diamond-shaped pattern is formed which gives the shock diamonds their name.