This is a visualization of the Rotating Vector Model (RVM). The inner sphere represents the neutron star. Radiation is assumed to be emitted outwards from near the stellar surface. Initially, its polarization will adiabatically change to follow the local magnetic field direction, up until the "polarization limiting radius" $r_\mathrm{pl}$, visualized as the larger translucent sphere. The bright cyan circle represents the intersection of the line-of-sight of an observer with the limiting sphere, and green curves are magnetic field lines crossing this circle. The orientation of these magnetic field lines determines the polarization directions the observer sees, which are visualized as red arrows. The vertical line represents the rotation axis.
The visualization is interactive. Feel free to drag around. You can change the observer angle and dipole inclination angle at the upper-right corner. "set_observer" will put the camera along the observer line of sight.