Shaped Sonic Boom Demonstration shock wave by a chase plane, the SSBD demonstrated a reduction in boom by about one-third. Several of the flights included NASA Dryden's F-15B research testbed aircraft following to measure the F-5E's shock wave signature close-up. During the flights, many shock wave patterns were measured by the F-15B at various distances and orientations from the F-5E. An unmodified F-5E flew a few seconds behind the demonstration aircraft to provide a baseline sonic boom measurement to validate the reduced boom produced by the demonstrator. A U.S. Air Force Test Pilot School Blanik L-23 glider carrying a microphone on the left wingtip,
Thunder K to about 30,000 K, then dropping away gradually to about 10,000 K. The average is about . This heating causes a rapid outward expansion, impacting the surrounding cooler air at a speed faster than sound would otherwise travel. The resultant outward-moving pulse is a shock wave, similar in principle to the shock wave formed by an explosion, or at the front of a supersonic aircraft. Experimental studies of simulated lightning have produced results largely consistent with this model, though there is continued debate about the precise physical mechanisms of the process. Other causes have also been proposed, relying on