Partially-insulated hts coils

Abstract

A high temperature superconducting, HTS, field coil. The HTS field coil has a plurality of turns and a semiconductor, arranged such that current can be shared between the turns via the semiconductor.

1 . A high temperature superconducting, HTS, field coil having a plurality of turns comprising HTS material, and a semiconductor, arranged such that current can be shared between turns via the semiconductor. 
     
     
         2 . An HTS field coil according to  claim 1 , wherein the HTS field coil has a radius greater than 50 cm. 
     
     
         3 . An HTS field coil according to  claim 1 , wherein the semiconductor is germanium. 
     
     
         4 . An HTS field coil according to  claim 1 , wherein each turn comprises a plurality of HTS tapes, and wherein a resistance between HTS tapes in each turn is less than a resistance between turns. 
     
     
         5 . An HTS field coil according to  claim 1 , wherein the semiconductor is provided as a layer of semiconductor between the turns. 
     
     
         6 . An HTS field coil according to  claim 1 , wherein the semiconductor has a resistivity between 10 −6  and 10 8  Ohm metres. 
     
     
         7 . A tokamak fusion reactor comprising an HTS field coil according to  claim 1 , wherein the HTS field coil is one of a toroidal field coil or a poloidal field coil. 
     
     
         8 . A proton beam therapy device comprising an HTS field coil according to  claim 1 , wherein the HTS field coil is one of:
 a field coil of an accelerator of the PBT device;   a dipole or quadrupole magnet of a proton beam steering system of the PBT device.