JITTER RADIATION MODEL OF THE CRAB GAMMA-RAY FLARES

The gamma-ray flares of the Crab nebula detected by the Fermi and AGILE satellites challenge our understanding of the physics of pulsars and their nebulae. The central problem is that the peak energy of the flares exceeds the maximum energy E-c determined by synchrotron radiation loss. However, when turbulent magnetic fields exist with scales lambda(B) smaller than 2 pi mc(2)/eB, jitter radiation can emit photons with energies higher than E-c. The scale required for the Crab flares is about two orders of magnitude less than the wavelength of the striped wind. We discuss a model in which the flares are triggered by plunging the high-density blobs into the termination shock. The observed hard spectral shape may be explained by the jitter mechanism. We make three observational predictions: first, the polarization degree will become lower in flares; second, no counterpart will be seen in TeV-PeV range; and third, the flare spectrum will not be harder than nu F-nu proportional to nu(1).