Shock Diamonds: Supersonic Heat Nuggets

• Shock diamonds, also known as Mach diamonds, are formed when an engine releases its exhaust into the atmosphere at a supersonic speed.

• The exhaust can be at lower pressure than atmospheric pressure at the same altitude. As it flows out, the atmosphere compresses it until the two pressures are equal.

• The exhaust may become overcompressed, expanding outward again to drop its pressure. This process may repeat multiple times until the exhaust pressure is close to the atmospheric pressure.

• This process generates waves in the exhaust plume, leading to the formation of shock diamonds.

• When atmospheric pressure bears down on the plume, the exhaust bends inward, increasing pressure and causing fuel burning. This combustion creates a bright spot, a shock diamond.