Exceptionally High Quality Home Made Video of SpaceX Iridium 4 launch 12/22/2017
The smoke rings are likely the first stage, the pulses are exhaust from the RCS (reaction control system) thrusters as it re-orients. At the point of detaching, Stage 1 is already at the edge of space, way too high for any significant aerodynamic effects. Just spectacular. I never get tired of this stuff.