In the heart of the tokomak reactor nuclear fusion takes place in the plasma of 150 million degrees Celsius. To keep that unimaginably hot plasma in check is an extremely strong magnetic field (13 Tesla) is required, which can only be efficiently generated by superconductors.
The wrist-thick braid cables (six) rising 13 meters in the fusion reactor are composed of interwoven strands of 0.8 mm thick. First three of these thin wires bundled with two of superconducting niobiumtin and copper. This makes the whole copper resistant to heating and preventing an unwanted sudden termination of the superconducting state.
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