Influence of Temperature and/or Field Dependences of the E−J Power Law on Trapped Magnetic Field in Bulk YBaCuO
Résumé
The dynamic response of cylindrical YBaCuO bulk part to magnetic field variations is calculated using the finite difference method. The pulsed field waveform results from a discharge of an RLC circuit. The computations are based on the heat diffusion equation with account of the heat produced by flux motion, and Maxwell's equations. A power law E-J is used to characterize the electromagnetic behaviour of the superconducting material. Numerical simulations showed that a major difference is obtained by taking account of the temperature and/or field dependence of the critical current density. Current density, temperature and magnetic field profiles as a function of time are reported. The influence of peak fields and pulse durations of the magnetization process are investigated. Comparisons concerning the achievable trapped magnetic field and the magnetic energy stored are made, and implications for the use of high-temperature superconductor bulk parts as cryo-permanent magnets in potential applications like electric machinery are discussed.