Interpolation of the Josephson interaction in highly anisotropic   superconductors from a solution of the two dimensional sine-Gordon equation
  In this paper we solve numerically the two dimensional elliptic sine-Gordon equation with appropriate boundary conditions. These boundary conditions are chosen to correspond to the Josephson interaction between two adjacent pancakes belonging to the same flux-line in a highly anisotropic superconductor. An extrapolation is obtained between the regimes of low and high separation of the pancakes. The resulting formula is a better candidate for use in numerical simulations than previously derived formulas. 
Yadin Y. Goldschmidt, Sandeep Tyagi