Current and voltage distribution in composite superconductors with resistive barriers - symmetric case

An equivalent symmetric scheme with distributed parameters is proposed, aim ing to simulate the current and voltage distribution in composite high-T-c superconductors with thin resistive barriers around the filaments. There ar e three longitudinal parallel branches in the scheme representing the super conducting core, the metallic inner matrix around this core and the outer m etallic matrix. Transversal current how is controlled by two interlayer ele ments: one represents the barrier inserted between the outer and inner matr ices, while the second simulates the interface resistance between inner mat rix and the superconducting core. The superconducting core may be fully res istanceless, but it can be found eventually in the resistive state. Two cases are discussed: first, the transport current is supplied into the composite conductor through the outer matrix and, second, the transport cur rent flowing fully in the superconducting core is forced to leave it due to some distortion of superconductivity. The governing relation in the scheme is the product of the matrix-supercond uctor interface conductance and the inner matrix resistance per unit length . Solution of the scheme leads to results that depend on the following dime nsionless relations. the ratio of the barrier to the matrix-superconductor interface conductances per unit length, the ratio of the outer to the inner matrix resistances per unit length and the ratio of the eventually resisti ve core resistance to the inner matrix resistance per unit length. The analytical results offer the possibility to calculate the longitudinal voltage distribution on the outer matrix surface and by this means to follo w the current distribution in the conductor cross section. They also allow one to calculate the typical current transfer lengths between the elements.