Encasing fusion plasma inside tungsten allowed a tokamak in France to set a new record by sustaining plasma at about 50 million degrees Celsius for six minutes. Tungsten has an extraordinarily high melting point. Using a tungsten-wall environment is for more challenging than using carbon, but the material allows physicists to sustain hot plasmas for longer and at higher energies and densities. While research into nuclear fusion has been slow, the field has made significant strides over the last few years.