Numerical Simulation of High-Temperature Superconducting Stacked-Tape Magnetic Lens via H-$\phi $ Model

Magnetic lens, exploiting the induced screening current, may concentrate the spatial magnetic flux. This concept has been realized by several research groups using GdBCO and/or MgB
₂
bulk superconductors. The limitation of the magnitude of concentrated flux density lies on the mechanical brittleness of the materials and the flux instability. High-temperature superconducting (HTS) tape possesses excellent mechanical and flux pinning properties and hence is a good candidate for magnetic lens. In this study, we implemented numerical simulations on the design of magnetic lenses using HTS stacked tapes. The models were constructed based on H-
$\phi $
formulations. We investigated and compared the concentration effect of various magnetic lenses with different topologies. The results show that a central field of 22.69 T and 25.62 T can be achieved respectively with rectangular-shaped stacks and X-shaped stacks in an applied magnetic field of 20 T. An optimized design of the magnetic lens has been proposed and correspondingly the mechanism for a better concentration-effect has been explained which provides a good reference for future experiments and applications.