rare-earth barium copper oxide · tape
REBCO tape
A layer of rare-earth barium copper oxide a few microns thick, grown on a metal tape, and the conductor that made a compact fusion magnet credible.
REBCO in numbers
- Transition temperature
- 92 K
- Made as
- tape
- Nitrogen line
- Above 77 K
What REBCO runs in today
High-field fusion magnets (the 20 T SPARC toroidal-field model coil, 2021); superconducting power cables.
Source: Textbook value for YBCO; Commonwealth Fusion Systems and MIT PSFC, 20 T large-bore demonstration, 2021
Why engineers choose REBCO
REBCO is the only conductor in service that still carries useful current at the field and temperature a compact tokamak is designed around, and the twenty-tesla model coil built in 2021 is the reason anyone believes that point is reachable. It is also barely a wire. The superconductor is a coating on a hundred times more tape, so the current flows in a plane. The critical current depends on which way the field crosses that plane. The tape cannot be transposed the way a round strand can. And a normal zone spreads along it slowly, so noticing a quench before it does damage becomes a design problem in its own right.
Where REBCO stops
REBCO almost never fails on physics. It fails on price per kiloamp-meter and on how many kilometers a supplier can deliver this year, which is a different kind of no and the one that stops the most programs.
Cost and scale-length
Clears the operating point, and the price is why you are asking.
Fields built on REBCO
- Transmission cableIn the ground under Shanghai, Essen and Long Island. Rare because of the cold.
- Fusion magnetsTwenty tesla, and the reason a compact tokamak is credible at all.
- Fault-current limitersGoes normal in a millisecond and swallows a short circuit.
- Wind generatorsA 3.6 MW superconducting rotor ran on a Danish turbine for 650 hours.
Terms used on this page about REBCO
SuperMatics is a platform infrastructure company for superconducting devices: software that finds the material and the process, lab work that makes and measures it, and pilot manufacturing with industrial partners.If a conductor on this page stops short of what your device needs, tell us about it.