X-Ray Scattering Evidence for Macroscopic Strong Pinning Centers in the   Sliding CDW state of NbSe_3
  Using high-resolution X-ray scattering techniques, we measure the variation, q(x), of the position in reciprocal space of the CDW satellite, in the sliding state, along the length of NbSe_3 whiskers. We show that structural defects and intentionally X-ray radiation-damaged regions increase locally the CDW pinning force, and induce CDW phase distortions which are consistent with those observed near contacts. Using the semi-microscopic model from Brazovskii describing the normal-condensed carrier conversion, with spatially varying parameters, we account for the experimental spatial dependence of the CDW phase gradient near both types of defects. 
D. Rideau, P. Monceau, R. Currat, H. Requardt, F. Nad, J.E. Lorenzo,   S. Brazovskii, C. Detlefs and G. Grubel