  A planet orbiting around a pulsar would be immersed in an ultra-relativistic
under-dense plasma flow. It would behave as a unipolar inductor, with a
significant potential drop along the planet. As for Io in Jupiter's
magnetosphere, there would be two stationary Alfv\'en waves, the Alfv\'en wings
(AW), attached to the planet. The AW would be supported by strong electric
currents, in some circumstances comparable to those of a pulsar. It would be a
cause of powerful radio waves emitted all along the AW, and highly collimated
through relativistic aberration. There would be a chance to detect these
radio-emissions from Earth. The emission would be pulses as for ordinary
pulsars; their occurrence would depend on the planet-star-observer angle. These
results are still preliminary, further work needs to be done.
