Radio Emission by Particles due to Pulsar Spin
  We present a relativistic model for the motion of charged particles in rotating magnetic field lines projected on to a plane perpendicular to the rotation axis. By making an approximation that the projected field lines are straight, an analytical expression is obtained for the particle trajectory. The motive behind developing this model is to elucidate some of the effects of rotation in pulsar profiles. There is a significant contribution to the curvature of particle trajectory due to the rotation of pulsar, which is in addition to the inherent curvature of the field lines. The asymmetry in the observed pulse shapes can be explained by considering the aberration-retardation effects. The single sign circular polarization that has been observed in many pulsars, might be due to the relative orientation of sight line with respect to the particle trajectory plane. 
R. M. C. Thomas and R. T. Gangadhara, (Indian Institute of   Astrophysics)