Abstract

Propagation effects on radio emission within the pulsar magnetosphere are discussed. Widely accepted pulsar models assume that a pulsar magnetosphere is populated with relativistic pair plasmas produced through electron–positron cascades by accelerated primary particles above the polar cap. Any radio emission produced well inside the light cylinder (the radius at which the rotation speed equals c) must propagate through the magnetospheric plasma and be subject to plasma dispersion effects such as refraction and absorption. The observed pulse profiles should contain some features that reflect the influence of the intervening plasma. I discuss particularly the absorption effect due to cyclotron resonance and its possible observational consequences.