2018ApJ...864..140P

We describe a geometric model for synchrotron radiation from blazar jets, involving multiple emission zones with turbulent magnetic fields and a transient core with a helical B-field. Including the effects of jet divergence, particle cooling, and the relativistic position angle rotation (RPAR) to the observer frame, we find polarization behavior consistent with recent data from monitoring campaigns. We predict that under some circumstances multi-π rotation phases should exhibit relativistically induced steps in rate dPA/dt and modulation in polarization Π that can be helpful in pinning down the jet Γ and θ_obs. Also, RPAR enhances waveband differences that will be particularly interesting for comparing radio, optical, and, soon, X-ray position angle and Π variations.