2000ApJ...541.1016L

We apply a theory of wave propagation through a turbulent medium to the scattering of radio waves in pulsar magnetospheres. We find that under conditions of strong density modulation the effects of magnetospheric scintillations in diffractive and refractive regimes may be observable. The most distinctive feature of the magnetospheric scintillations is their independence of frequency.
Result. based on diffractive scattering due to small-scale inhomogeneities give a scattering angle that may be as large as 0.1 rad and a typical decorrelation time of 10^–8 s. Refractive scattering due to large-scale inhomogeneities is also possible, with a typical angle of 10^–3 rad and a correlation time of the order of 10^–4 s. Temporal variation in the plasma density may also result in a delay time of the order of 10^–4 s. The different scaling of the above quantities with frequency may allow one to distinguish the effects of propagation through a pulsar magnetosphere from the interstellar medium. In particular, we expect that the magnetospheric scintillations are relatively more important for nearby pulsars when observed at high frequencies. If confirmed, these results would provide a direct testing of the plasma inside the light cylinder.