ABSTRACT
Since many books and reviews have already been published' describing the theory
of type-II superconductors, it is necessary here to give only a brief summary
of properties and to single out specific characteristics that are important for the
loss problem. In a type-I superconductor, at temperatures below its transition
temperature Tc, magnetic flux does not penetrate beyond a small penetration depth
k, and the interior of the superconductor is described by the condition B = 0. If a
body in its normal state already has flux in the interior, the flux is expelled when
the material goes superconducting. Such behavior is called the Meissner effect.
