  We study the distribution of bulk superconductivity in presence of an applied
magnetic field, supposed to be a step function, modeled by the Ginzburg-Landau
theory. Our results are valid for the minimizers of the two-dimensional
Ginzburg-Landau functional with a large Ginzburg-Landau parameter and with an
applied magnetic field of intensity comparable with the Ginzburg-Landau
parameter.
