This is an excerpt from EERE Network News, a weekly electronic newsletter.

April 30, 2003

Sandia's "Z Machine" Reveals New Approach to Fusion Energy

As renewable energy assumes a growing role in the world energy mix, will nuclear fusion be next? Physicists and engineers have been working for decades to recreate the sun's energy source in a controlled reaction that could be used as a source of energy here on Earth. They have traditionally touted one of two approaches: magnetic confinement, in which a hot plasma is held in a magnetic "bottle," and inertial confinement, in which a high-energy beam (usually a laser) implodes a pea-sized target, causing its nuclei to fuse. But in early April, researchers at DOE's Sandia National Laboratories showed that they have a third way.

The Sandia researchers started with a pea-sized target of deuterium, much like in an inertial confinement machine, but placed that inside a foam cylinder surrounded by hair-thin tungsten wires. By running huge, precisely timed pulses of electricity into that tungsten-wire cage, they created intense magnetic fields that crushed the tungsten wires into the foam cylinder, generating X-rays. Those X-rays, in turn, produced a shock wave that imploded the target, much like the laser beams do in an inertial confinement machine.

Sandia researchers had their first suggestion that they had achieved fusion in the Z machine when they measured neutron pulses coming from implosions last summer. In April, they announced that they had, indeed, produced nuclear fusion. See the Sandia press release.

Unfortunately, the path from creating fusion to building a practical fusion energy source is a long and difficult one. Although magnetic confinement has been studied for decades, DOE announced in January that it was joining an international effort to advance that technology, a project that is not expected to start operating until 2014. DOE expects the project to yield fusion research findings for up to 20 years. See the DOE press release.