Superconducting trapped-field magnets: Temperature and field distributions during pulsed-field activation

Abstract

We calculate the temperature and magnetic field distributions in a bulk superconductor during the process of pulsed-field magnetic activation. The calculations are based on the heat diffusion equation with account of the heat produced by flux motion, and the critical state model with temperature dependent critical current density. For a given activation time the total amount of trapped flux Φ is maximum for an optimal value Bopt of the maximal applied field. We analyze how Bopt and Φ depend on the material parameters and the field ramp rate.

Reliable 4.8 T trapped magnetic fields in Gd–Ba–Cu–O bulk superconductors using pulsed field magnetization

“…The first pulse of 2.99 T was slightly smaller than the Bj at 70 K which partially magnetized the sample at the periphery where heat was generated [36]. The effect of this two-step method can be evidently found in figure 4(b) where the temperature rise for single-and multi-pulse PFM at 30 K (red open and solid circles) was compared.…”

Local measurements of the magnetization process of bulk superconductors induced by a pulsed magnetic field

“…From application perspective, pulse field magnetization (PFM) is more feasible because a large current has to be fed only for a very short time and the magnetizing coil can be made small [2; 3]. PFM is, however, less effective than the FC method because of the heat that is generated by the dissipative motion of flux lines [2][3][4][5][6]. Most significantly, the difference in the trapped field with the FC method tends to escalate when the ability of trapping flux lines increases by improving the material characteristic or by decreasing the temperature.…”

Numerical study of the influence of flux creep and of thermal effect on dynamic behaviour of magnetic levitation systems with a high-Tcsuperconductor using control volume method

“…For the used material in our work (YBaCuo), the good value of n is taken equal to 20 at T = 77 K [13]. In this paper we have adopted a linear model to describe the dependence of the critical current on temperature [19]:…”