Circularly-polarized nanoshot pairs from the Crab pulsar

We discover that multiple nanoshot pairs separated uniformly by about 21{μ}s exist in a giant radio pulse from the Crab pulsar. In a few of such pairs, two nanoshots are left-hand and righthand circularly polarized, respectively. This nanoshot pair with both signs of circular polarization is proposed to produce through splitting of a linearly-polarized nanoshot by the extreme Faraday effect, which relies on highly-asymmetrical pair plasma and intense fields of nanoshots. Asymmetrical pair plasmas should be related to discharge activities in the pulsar. Nanoshot fields are strong enough to induce cyclotron resonance in the magnetosphere, which significantly reduces the speed of right-circularly polarized mode. This work implies that nanoshots are generated in the inner magnetosphere, and can also explain the circular polarization and reversed Faraday rotation of fast ratio bursts from magnetars.