Thrusts for HTS Magnets 

Why do we need HTS magnets? HTS more competitive than LTS or copper magnet

  • HTS can generate higher magnetic field than LTS or copper by virtue of high Ic at the same T
  • Technological/engineering
    • Easier to operate (higher temperature)
    • Smaller to design and manufacture; compact size and lighter weight enhance portability and ease of use in various applications, including transportation and aerospace industries
  • Scientific: HTS magnet essential to novel scientific finding/research
    • Certain scientific research requires ever-higher magnetic field
    • Only HTS can respond to such requirements
  • Environmental
    • Consume less power to run and less materials due to higher current density

Markets for HTS Magnets – Status Quo

Superconductivity and its Operating Region

  • In the superconducting state (typically at cryogenic temperatures), no electrical resistance → much larger electric currents → stronger magnetic fields and cheaper op cost
  • Critical surface of superconductivity
  • Lower temperature, lower current, lower magnetic field  
    → lower probability of losing superconductivity

Quench and its Different Behaviors in LTS and HTS

  • Quench (= thermal runaway)
    • Superconducting coil into the normal (resistive) state →  abnormal termination of magnet operation
    • Inevitable and unpredictable
    • Must protect magnet from burning, in the event of quench
  • Main differences between LTS and HTS wires
    • Quench propagation speed: LTS ≫ HTS
    • Conductor shape: round wire (LTS), thin tape (HTS)

Stabilizers in LTS and HTS Magnets

No Insulation (NI) HTS Magnet

  • Capable of avoiding ‘direct’ burning
    • Postpone burning by virtue of stopgap
    • Hailed as a savior to resolve the HTS nemesis “quench” and to finally realize HTS commercialization
  • Status Quo: one big issue down but still many remaining ones before commercialization
    • Quench detection essential but can it be done in a timely manner?
    • Very slow and lossy field control (including startup)
    • Heat in varying field or current (eddy current)