Fusion analysis suggests promise for smaller, cheaper reactors

Alan Costley, a physicist working for the company Tokomak Solutions in Culham, Oxfordshire, has written a paper in the journal Nuclear Fusion which suggests that there may only be a weak link between the size of a magnetic-confinement fusion reactor and the point at which it produces more power than it takes to operate.

Until now, most fusion research has focused on the principle that ‘bigger is better’. The best-researched and most advanced form of nuclear fusion device is the tokamak, a toroidal (doughnut-shaped) vacuum vessel surrounded by powerful electromagnets that both confine a hydrogen plasma (a mixture of different isotopes of hydrogen, in a state where their charged nuclei are separated from their associated electrons) and force the plasma particles to circulate around the torus. The combination of the magnetic squeezing and the speed of the particles (to which other devices also contribute) forces the nuclei to collide at high energies, fusing together to form helium nuclei and releasing a burst of energy.