I was recently reading about sonic booms and learned that when the speed of source is greater than or equal to the speed of sound in the medium, then a sonic boom is produced.
However, I could only understand why sonic booms are produced when the source speed is equal to the speed of sound.
When the source emits a compressional pulse, it virtually remains fixed to the source, as both move at the same speed.
Now when a second compressional pulse is produced, it constructively overlaps with the initial pulse, and so on the amplitude keeps getting really large and results in a sonic boom.
However, when the speed of the source is higher than the speed of sound, I couldn't figure out the same logic, especially when the source travels towards the observer in a straight line.
For instance, if the speed of the source is twice the speed of sound, it emits a compressional pulse, travels ahead of the wave, and in a further point in space emits another pulse.
I can only see a constant distance between these pulses, and I cannot see how they would constructively interfere to give a sonic boom felt by the observer who is along the line that the source travels.
Would appreciate help in understanding what actually happens in the second part.