1. The National Institute for Fusion Science (NIFS), of the National Institutes of Natural Sciences (NINS) in Japan, has achieved an electrical current of 100,000 amperes, which is by far the highest in the world, by using the new idea of assembling the state-of-the-art yttrium-based high-temperature superconducting tapes to fabricate a large-scale magnet conductor.
Using the state-of-the-art yttrium-based high-temperature superconducting tapes which have been developed and produced in Japan through the new thinking that simply stacks the tapes, NIFS manufactured a conductor of exceptional mechanical strength.
For the conductor joints, which are important for the production of the large-scale coils, NIFS developed low-resistance joint technology through collaborative research with Tohoku University.
As a result of the prototype conductor test, at the absolute temperature of 20 degrees Kelvin (minus 253 degrees Celsius) the electrical current exceeds 100,000 amperes.
The overall current density exceeds 40 A/mm2 including the jackets, and this value is of practical use for manufacturing large-scale fusion reactor magnets.
This result is of global importance. The team uses 54 yttrium-based high-temperature superconducting tapes. Each tape is 10 mm in width and 0.2 mm in thickness.
2. Cambridge researchers managed to ‘trap’ a magnetic field with a strength of 17.6 Tesla – roughly 100 times stronger than the field generated by a typical fridge magnet – in a high temperature gadolinium barium copper oxide (GdBCO) superconductor, beating the previous record by 0.4 Tesla.
Superconductors are currently used in scientific and medical applications, such as MRI scanners, and in the future could be used to protect the national grid and increase energy efficiency, due to the amount of electrical current they can carry without losing energy.
The current carried by a superconductor also generates a magnetic field, and the more field strength that can be contained within the superconductor, the more current it can carry. State of the art, practical superconductors can carry currents that are typically 100 times greater than copper, which gives them considerable performance advantages over conventional conductors and permanent magnets.
The new record was achieved using 25 mm diameter samples of GdBCO high temperature superconductor fabricated in the form of a large, single grain using an established melt processing method and reinforced using a relatively simple technique. The previous record of 17.24 Tesla, set in 2003 by a team led by Professor Masato Murakami from the Shibaura Institute of Technology in Japan, used a highly specialised type of superconductor of a similar, but subtly different, composition and structure.