Analytical Calculation of the Instantaneous Power in a Current Carrying Superconducting Tube With J C

Abstract—To use high-Tc superconductors for alternating cur-rent transport, it is important to evaluate AC losses. The influence of J c (B) on the self field losses in a superconductive tube fed by a transport current in incomplete penetration is studied for two reasons. First, superconducting power cables have a geometry that resembles a tube and second, for high-temperature superconduc-tors, the variation of J c (B) is important especially for low mag-netic fields like self field. An analytical calculation of the distribu-tion of the magnetic field B(r; t) by using a linearized law J c (B) is presented. FromB(r; t) one deduces J(r; t) andE(r; t). The an-alytical expressions of those were used to calculate the analytical instantaneous power p(t). The losses in the superconducting tube are the average value of p(t). They are numerically calculated and compared with the measurements taken on a sample whose charac-teristic J c (B)was previously measured. With the linear model, the calculated losses are closer to the measured losses than for the Bean model, but the J c (B) identification remains the main problem