The Teslarati article SpaceX delivers largest commercial satellite in kick off of Falcon 9 marathon includes several beautiful photos, of the Telstar 19V launch, including the one below.
It shows what looks like a "smoke ring" or vortex ring. Without video though, it's hard to be sure that it's a proper vortex ring which should show some rolling motion around the circe of the torus.
While the caption for the image says:
B1047 created an extraordinary ring vortex rainbow as it smashed through Max Q, the point of highest aerodynamic stress on the rocket.
I don't see how this could be an explanation. Dramatic things do happen when one crosses mach-1 or "the sound barrier" (see image and linked discussion below, there is no "barrier", no barriers were harmed in the making of this photo) but reaching the maximum of something, or any extremum or inflection point implies a leveling off of something, where the first derivative is zero and nothing "suddenly happens". Max-Q becomes a fuzzy concept when a realistic rocket at a non-zero angle of attack is considered, and the total aerodynamic loading needs to be integrated over the entire craft, and not just the point of a theoretical nose cone.
Question: So I'd like to understand better if this is really a vortex ring to begin with, and if so, what caused it, and if the "instant of Max-Q" is really when it happened and "smashing through" it is the cause.
above: "B1047 created an extraordinary ring vortex rainbow as it smashed through Max Q, the point of highest aerodynamic stress on the rocket. (Tom Cross)" From here.
click each for full size
right: From Atlas Obscura's The Wildly Misunderstood Aeronautics Event Captured in This Photograph. See also NASA's NTRS 19950024579 Patterns in the sky: Natural visualization of aircraft flow fields.