Apparent resistance of non-ideal type II superconductors

The emergence of some apparent resistance is discussed for different cases of inductive as well as of non-inductive coils wound with non-ideal type II superconductors and placed into an external magnetic field oscillating with some low frequency. For the situation where these coils can be regarded as concentrated elements of an electric circuit the general expression for the terminal voltage of the coils has been derived along with equations determining the decay of the current in the closed superconducting circuit. The results of experimental investigations of the current decay in such coils and of their terminal characteristics showing a good agreement with the theory are also presented.