Superconducting magnet for producing part of a substantially toroidal field

摘要

A first set of conductors (legs 231) joined in an alternate fashion to a second set of conductors (legs 232) to form at least part of the winding of a magnet 230 that produces a toroidal field (see fig 1). The two conductor sets comprise different superconductors. In this way, different properties (e.g. critical current, upper critical field, critical temperature) of different superconductors may be taken advantage of. The inner legs may be made of a high temperature superconductor (HTS) such as YBCO whereas the outer legs may be a low temperature superconductor (LTS) such as NbTi (niobium-titanium). Each first set conductor (inner leg) passes through the midplane of the toroidal field and is closer to the central axis of the toroidal field than each second set conductor (outer leg). The inner conductors may be straight whereas the outer ones may be curved. The two sets of conductors may be connected at joints 233 and may be demountable. The conductors 231, 232 together may form a distorted (half-phi) helix shaped magnet coil of a tokamak.