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)