The effect of differential refraction on wave propagation in rotating   pulsar magnetospheres
  Refraction of wave propagation in a corotating pulsar magnetospheric plasma is considered as a possible interpretation for observed asymmetric pulse profiles with multiple components. The pulsar radio emission produced inside the magnetosphere propagates outward through the rotating magnetosphere, subject to refraction by the intervening plasma that is spatially inhomogeneous. Both effects of a relativistic distribution of the plasma and rotation on wave propagation are considered. It is shown that refraction coupled with rotation can produce asymmetric conal structures of the profile. The differential refraction due to the rotation can cause the conal structures to skew toward the rotation direction and lead to asymmetry in relative intensities between the leading and trailing components. Both of these features are potentially observable. 
D. Fussell, Q. Luo