Understanding the enigmatic "zebra"-like spectrum of the Crab pulsar radio interpulse

The Crab pulsar radio emission exhibits a peculiar spectral band structure. Despite being known for almost 20 years, this structure has so far been hard to explain. The model explaining the spectral "zebra" pattern of the high-frequency interpulse (HFIP) of the Crab pulsar radio emission is proposed. The observed emission bands are interference fringes in the spectral domain. The pulsar's own plasma-filled magnetosphere residing in a strong gravitational field plays a role of a frequency-dependent lens – or, more accurately, a "crystal ball". The observed features such as the proportional band spacing, high polarization, constant position angle, and others are naturally explained. The model is testable, and exciting predictions are made for observations in the mm/sub-mm range. Furthermore, the technique allows one to perform real "tomography" of the pulsar magnetosphere, that is, in essence, resolving sizes of a few tens of km at the distance of 2 kpc.