Two-dimensional models of the magnetic-field enhancement at pit and bump
  Formulae of magnetic field enhancement at a two-dimensional semi-elliptical bump and a two-dimensional pit with chamfered edges are derived by using the method of conformal mapping. The latter can be regarded as an approximated model of the two-dimensional pit with round edges. 
Takayuki Kubo
physics.acc-ph cond-mat.supr-con