Nuclear fusion with rare-earth magnets: A spark for (almost) free energy?
Researchers at the Princeton Plasma Physics Laboratory (PPPL) have developed a new stellarator-type fusion reactor. PPPL produced the first reactor of this kind 70 years ago. While that earlier project was not economically viable, the new Muse stellarator could even revolutionize existing nuclear fusion reactors. Instead of relying on electric magnetic coils, its designers used permanent magnets made from rare earths.
No electric current destabilises the plasma
To date, nuclear fusion research has focused primarily on tokamak reactors, in which the plasma is confined by ring-shaped magnetic coils. In such reactors, however, current flows through the plasma, which can make it unstable. Scientists at PPPL have solved this problem. The Muse reactor requires no electrical voltage and can therefore run for an indefinite period without an energy input.
A magnetic field optimised by a factor of 100
Manufacturing and arranging the magnets in permanent-magnet stellarators is very difficult, meaning that the results of earlier experiments offered neither practical nor economically viable outcomes for further development of nuclear fusion. The Muse reactor, however, was able to confine the plasma optimally thanks to a special property: outstanding quasi-symmetry. Put simply, this means that the shape of the magnetic field inside the stellarator does not match the shape of the field around the stellarator. According to PPPL’s research team, Muse’s quasi-symmetry is 100 times that of a conventional stellarator reactor. In addition, Muse’s rare-earth magnets have a field strength of 1.2 tesla. This is well above that of conventional ferrite or ceramic rare-earth magnets, which is between 0.5 and 1 tesla.
No high-performance permanent magnets without rare earths
High-performance permanent magnets such as those used in the new stellarator reactors cannot be produced without the four most important rare-earth magnet elements. Neodymium oxide accounts for the largest share of the mass of such magnets, but heavy rare earths such as terbium oxide and dysprosium oxide are also indispensable due to their special properties. For example, they protect the magnets from demagnetisation at high temperatures, which is essential in the field of nuclear fusion.
Capital Markets Union signals €500 billion in investment opportunities
Because research into nuclear fusion as an (almost) cost-free energy source is already so advanced, policymakers are calling for investment. During a recent visit to the Max Planck Institute for Plasma Physics (IPP) in Garching near Munich, European Commission President Ursula von der Leyen advocated improved framework conditions for nuclear fusion as a future energy source. To achieve this, the Capital Markets Union must be advanced at European level. This could create an additional €500 billion in investment opportunities each year.
Invest in nuclear fusion now—via rare earths
Private investors can already invest in nuclear fusion. This is because, particularly if the new stellarator reactors prevail, manufacturers will require vast quantities of these critical commodities.