On the origin of the torus and jet-like structures in the centre of Crab   Nebula
  The formation of the toroidal and jet-like structures in the central part of the Crab Nebula is explained in the framework of Kennel & Coroniti theory. The only new element introduced by us in this theory is the initial anisotropy of the energy flux in the wind. We estimate the X-ray surface brightness of the Crab Nebula from the region of interaction of this wind with the interstellar medium and compare it with observations. 
S. V. Bogovalov, D.V. Khangoulian