A serious contender in the race for fusion energy could emerge from a once obscure program at New Mexico's Sandia National Laboratories. In a letter to the Department of Energy (DOE) on Monday, Sandia officials proposed a new facility that they say could generate 10 times more fusion energy at about one-third the cost of the $1.2 billion National Ignition Facility (NIF) now being built at Lawrence Livermore National Laboratory in California. Experts say that much more detailed studies are needed to see if these projections are realistic.
Both NIF and Sandia's proposed "X-1" facility would ignite fusion in a pellet of hydrogen isotopes. While NIF would do so by crushing the pellet with pulses from a gargantuan laser, X-1 would use x-rays from a plasma imploding after an array of wires is vaporized by a jolt of electric current. Work to date has been done on a smaller device called a Z-pinch, and Sandia's letter to DOE is seeking permission to begin conceptual design studies for the more powerful X-1 machine.
Over the last several months, the Z group--involving about 60 physicists at Sandia, Los Alamos National Laboratory, and Livermore--has measured an x-ray "temperature," or energy density, of about 1.8 million degrees. That's high enough to suggest that the souped-up X-1 could ignite a larger fusion burn than NIF, says Donald Cook, director of Sandia's Pulsed Power Sciences Center. Other researchers emphasize that the concept has received little detailed study compared to laser fusion.
Sandia's letter to DOE is just the first step in a long process of seeking funding for the device. "There are a lot of projects vying for attention," says a congressional staffer. Nevertheless, says one DOE official, X-1 "is a serious proposal that deserves careful attention and review."