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What is a superconductor, and why does fusion need one?
A superconductor carries electricity with zero resistance. High-temperature superconductors make the strong, efficient magnets that compact fusion depends on.
Superconductivity is what makes a compact high-field tokamak possible at all. See high-temperature superconductivity, REBCO magnets, and why such a strong field?
Questions & answers
What is a superconductor?
A material that, below a certain temperature, carries electric current with exactly zero resistance — no heating, no energy loss. That lets it sustain enormous currents and therefore very strong magnetic fields continuously, which ordinary conductors could never do without melting.
Why does fusion need superconductors?
Because fusion power density rises steeply with magnetic field, and only superconducting magnets can produce and hold the necessary field efficiently. Kronos uses high-temperature superconductor (REBCO), which stays superconducting at higher fields and warmer temperatures than older materials.
What's special about high-temperature superconductors?
They reach fields (24.6 T for Kronos) that low-temperature superconductors can't, and they run near 20 K instead of 4 K — easing the cooling. HTS is the enabling technology behind the whole compact-fusion approach.