Penetration of a weak magnetic field in inhomogeneous type-II superconductors

It is a well known fact that most superconducting materials are inhomogeneous. So the London theory is formulated for this case. The obtained equation is solved for the case of the spatial distribution of the number density of superconducting electrons, ns=n0exp-μx (where 1/μ is the characteristic length of the distribution and x is the coordinate). The presence of the electrostatic field inside inhomogeneous superconductors is discussed. (orig.)