Nearer the 'sun's fire'

The article discusses Asdex, the largest fusion reactor in Europe and the function of the magnetic fields that are needed to control the plasma generated in the reactor. The magnetic field is not so dense as physicists might wish. Energy particles manage to reach the wall of the vessel, where they dislodge cold metal atoms. Eventualy this leads to an enormous degree of cooling. To keep plasma from losing its resistance at temperatures over ten millian degrees, Asdex uses neutral-particle injectors