1999A&A...352..489K

We have performed a comparative analysis of the frequency dependence of the profile widths of millisecond and normal pulsars. In this study we combine our 102MHz observations with data at higher frequencies borrowed from the literature. We find that the profile width of millisecond pulsars remains nearly constant in the frequency range between 102 and 1400MHz. This is in contrast with what is known for much slower pulsars where typically the pulse profile narrows significantly at the same frequency range. Our findings indicate that the geometry of the radio emission region of millisecond pulsars differs from that of normal pulsars. We therefore suggest that either the magnetic field configuration in millisecond pulsar magnetospheres deviates from that of a pure dipole, or (and) the radio emission region is compressed.