A tokamak in France set a new record in fusion plasma by encasing its reaction in tungsten, a heat-resistant metal that allows physicists to sustain hot plasmas for longer, and at higher energies and densities than carbon tokamaks.

A tokamak is a torus- (doughnut-) shaped fusion device that confines plasma using magnetic fields, allowing scientists to fiddle with the superheated material and induce fusion reactions. The recent achievement was made in WEST (tungsten (W) Environment in Steady-state Tokamak), a tokamak operated by the French Alternative Energies and Atomic Energy Commission (CEA).