Interchange of current between shunt layer and HTS film in long coated tapes

In long-length HTS coated metallic tapes a shunt layer is required to subdue the influence of the hot spots as well as to equalize the potential between the HTS film and the metallic tape in the case when the transport current is near to its critical value. Both a modelling and measurements of current transfer between current contact, shunt layer and HTS film have been performed to optimize the architecture of the coated tapes. The model of current interchange allows to determine analytically the total power losses as well as the surface density of the power losses at the contact areas. Expressions derived for power dissipation lead to a criterion for the contact resistance, R s, and the length of the current contact, L, of the given HTS/shunt/contact architecture. For a combination of YBCO and Au layers, for example, the R s must be