THERMAL-EXPANSION OF 2 NORMAL PHASES ALONG A CURRENT-CARRYING INHOMOGENEOUS SUPERCONDUCTING WIRE

We present a theoretical model which describes the thermal expansion o f one or two normal phases along a current-carrying type-I inhomogeneo us superconducting wire. We derive explicit formulas for the longitudi nal propagation velocity in the case of low regimes using a quasi-stat ionary approximation of the heat equation, as well as for the onset of thermal destruction of superconductivity. In the case of two normal p hases propagating in opposite directions, the model predicts a yet uno bserved thermal interaction at distances d of the order of the diamete r of the wire. Depending on the local resistivity value and the distan ce d, the propagation velocity may change considerably. The prediction s of the model ave in good agreement with the available experimental d arn.