These are nice shots...in fact very nice shots. I can honestly say that my personal stash of photos do not include such quality images. I'd have to go to the web and dig some up. I was trying to stick with shots taken by me and my buds, but I can go to some of my friends' squadron archives and dig out some better ones, if that is what the audience demands.
The combination of the shock wave, generated by the supersonic flight, and the humidity present at the scene of the supersonic flight create the vapors that make the shock wave visible. If you don't have the right conditions, the shockwave goes un-noticed to the eye, but is plainly heard to the ear in the form of a sonic boom.