Schematic illustration of the polarization from synchrotron emission from a toroidal magnetic field. Left: illustration of the emission of the photons toward an observer with a line of sight forming a viewing angle 0„ with the jet. The emission stems from a magnetic field whose lines are indicated in purple. The gray area corresponds to the area (with a size of 1/Γ) which is seen by the observer. Right: the observer sees the emission area with a size of 1/Γ (shown in gray) within the jet (shown in purple). The polarization vectors of the photons are indicated as black arrows with the direction indicating the PA and the size representing the PD. For an observer for whom the observer area is contained within the jet, the ordered magnetic field lines allow for the observation of a significant level of polarization. In case the observed area becomes equal to the size of the jet, the polarization will start to cancel out, resulting in a low PD.