National Geographic : 1959 Sep
"Mach diamonds"-shock waves produced by jet exhaust-spout from an F3H fighter as the pilot cuts in his afterburner. This device, used for bursts of emergency power in take-offs or duels with enemy fighters, dumps fuel into an auxiliary firing chamber, enormously boosting the jet's thrust. One pilot likened the afterburner to the passing gear on a car. "The only difference," he said, "is a few hundred miles an hour."