The mode-separated pulse profiles of pulsar radio emission

Two modes of orthogonal polarization are generally observed in the radio em ission from pulsars. Essentially all attempts to calculate the average prof iles of the individual modes have assumed that the modes occur separately. We have presented evidence, however, that the modes occur simultaneously. T herefore, we believe that "mode-separated" pulse profiles that have been pu blished to date reveal little about the polarization properties of the indi vidual modes. Calculating mode-separated pulse profiles for superposed orth ogonal modes is complicated by the unknown polarization properties of the i ndividual modes. However, the simplest model of pulsar radio emission that can explain the wide variety in the emission's polarization is one in which the individual modes are completely polarized. We argue that the orthogona l modes in PSR B0525+21 and PSR B2020+28 are highly polarized and use our s imple model to compute the average profiles of their orthogonal modes. For both pulsars, the total intensity of the two mode profiles resembles the ov erall pulse profile, and each profile is highly linearly polarized.