Abstract
The local model of non-ideal type-II superconductors with pinning force is presented by modifying a general solution of the London equation. The local field around the core is deformed by the transport current. This deformation satisfies the London equation and is represented in a form so that the nature of the pinning force is included. The critical current density Jc is given by polynomial Jc=∑\\limitsm=1A2m-1Jt(2m-1), and the first term Jt1 agrees with that in the Coffey's model (Phys. Rev. 166 (1968) 447) which explains the experimental results on Nb3Sn and heat-treated Nb-22at.%Ti. Inclusion of terms with m>1 can explain a variety of Jc-H plateau curves, peak effect, etc. The amplitude A2m-1 and mode m of the deformation vary with the kinds of lattice defects to pin fluxoids, and these are required to be independent of an applied magnetic field, but dependent on the temperature.
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