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Superconductivity is a miracle of physics: when cooled down to temperatures close to absolute zero, certain alloys, or compounds, cease to oppose resistance to the passage of electricity. In electromagnets made of superconducting coils like ITER's, electrical consumption drops to zero and, as an added advantage, no heat is generated inside the magnets.

Magnet cooling, however, requires a vast quantity of energy. Cooling fluids must be circulated through the entire length of the superconducting coils which, at ITER, means maintaining a forced flow of 25 tonnes of liquid helium at 4 K (minus 269 °C) throughout approximately 180 kilometres (and 10,000 tonnes) of conductor.

For many years, research worldwide has struggled to develop materials that would transition to the superconducting state at less frigid temperatures—so-called "high-temperature" superconductors.

Used in electromagnets, these "high-temperature" superconductors would allow the production of more powerful magnetic fields, passing the present limitation of low-temperature conductors (At its maximum in the centre of the ITER central solenoid, the magnetic field has an intensity of 13 Tesla.)

The National High Magnetic Field Laboratory in Tallahassee, Florida, recently announced an important breakthrough in the quest for "high-temperature" superconductors: the manufacturing and testing of a half-pint "little big coil" that operated inside the bore of large outer copper coil in a background field of approximately 30 T, itself generating an additional 14.4 T, thus generating a combined record magnetic field of 45.5 Tesla in its (small) bore. This experiment demonstrated the capability of high temperature superconductors to operate in very high magnetic fields under large stresses. This could open the way to a new generation of magnets for biomedical research and fusion reactors.

 More information on the National High Magnetic Field Laboratory website and in this month's issue of Nature.

Every two years, the Festival de Théorie aims to promote interactions between PhD students, postdocs and young scientists in fusion plasma physics and related fields including astrophysics, fluid mechanics and geophysics.

Many of the principles governing the turbulence and magneto-hydrodynamic phenomena observed in fusion plasmas are similar to those found in naturally occurring astrophysical plasmas in the Sun. Fluid mechanics and planetary atmospheric physics also share common threads, reporting observations that often reflect the experimental measurements taken in tokamaks. This is where the Festival de Théorie comes in, fostering cross-disciplinary collaboration and providing an invaluable forum for tackling some of the key issues posed by ITER.

The theme selected this year is: Phase Dynamics. The 2019 program is organized around four weeks of study and research in collaboration with a core group of prominent scientists. Participants begin with two weeks of seminars and lectures, followed by research projects in weeks 3 and 4 on topics spanning plasma physics, fluid dynamics, astrophysics, and applied mathematics.

The 10th edition of the Festival de Théorie will take place in Aix-en-Provence, France, from 1 to 26 July 2019. Registration is open now.