Magnetic fields and currents for two current-carrying parallel coplanar superconducting strips in a perpendicular magnetic field

We present general solutions for the Meissner-state magnetic-field and current-density distributions for a pair of parallel, coplanar superconducting strips carrying arbitrary but subcritical currents in a perpendicular magnetic field. From these solutions we calculate (a) the inductance per unit length when the strips carry equal and opposite currents, (b) flux focusing in an applied field-how much flux per unit length is focused into the slot between the two strips when each strip carries no net current, (c) the current distribution for the zero-flux quantum state when the strips are connected with superconducting links at the ends and (d) the current and field distributions around both strips when only one of the strips carries a net current. The solutions are closely related to those found recently for the magnetic-field and current-density distributions in a thin, bulk-pinning-free, type-II superconducting strip with a geometrical barrier when the strip carries a current in a perpendicular applied field.