Rocket staging -- it blooms like that because there's very little atmosphere up there (gaseous diffusion). It's lit by the sun which while setting from the ground view, is in full view to light up the rocket exhaust. The first stage's engine is optimized for in-atmosphere operation (small nozzle) while the subsequent stages are optimized for vacuum operation (large nozzle). The shockwaves are due to being faster than the speed of sound, the shockwaves interact with the exhaust that's being lit by the sun.