At first glance, something seems to be missing from the diagram Jay Kesner is describing. The lack of supports is not a draftsman's oversight. Kesner and his colleagues plan to levitate the ring magnetically as part of a novel experiment that may ultimately lead to a simple, safe, and inexpensive fusion power source. Thermonuclear fusion is the engine that powers the sun and stars. At tremendous stellar temperatures and the pressures of intense gravitational fields, hydrogen nuclei are driven together until they fuse, forming helium and releasing energy.
Similar reactions occur briefly during the detonation of thermonuclear warheads.
In magnetic confinement fusion machines, physicists mimic the conditions inside stars by heating plasma trapped in magnetic, rather than gravitational, fields. For nearly 30 years, doughnut-shaped magnetic confinement machines called tokamaks received the most attention and funding for potential fusion power production. These intricate devices have produced impressive bursts of energy and remain at the forefront of fusion research. But according to Dale Meade, who heads the Advanced Fusion Concepts group at Princeton University, tokamaks and related machines are plagued by various types of turbulence that cause the plasma to leak out. Surmounting these challenges, says Meade, requires either advances in machine design or dramatically scaled-up, and expensive, devices.