With regard to the F 22 photos; what causes the "balls" of fire or plasma in some jet exhaust photos? For continuous combustion the exhaust should be steady like a propane torch flame with the blue cone.

   Dale Davies

They called Mach Diamonds. (or shock diamonds) due to standing supersonic shock waves in the exhaust plume.

http://en.m.wikipedia.org/wiki/Shock_diamond

Phill Hinds
George Town TAS


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