atmospheric focusing atmospheric reentry blast wave bow shock bow wave breaker chapman-jouguet condition chromosphere corona critical mach number density detonation electromagnetic field gas hydraulic jump light cone liquid ludwig prandtl mach number mach wave magnetopause magnetosphere mean free path moving shock oblique shock ocean surface wave order of magnitude pressure ramjet refraction schlieren photography scramjet shadowgraph shock front shock waves shock diamond shock tube shore solid soliton sonic boom special relativity speed of light speed of sound sun supersonic surface normal temperature trinitrotoluene undercompressive shock wave vacuum velocity water wave wave drag