An electrical circuit that should carry enough power to produce the long-sought goal of controlled high-yield nuclear fusion and, equally important, do it every 10 seconds, has undergone extensive preliminary experiments and computer simulations at Sandia National Laboratories' Z machine facility. It has been reliably used 11,000 times.
From Siberia, not Area 51: Sandia researcher Bill Fowler tests circuits on an LTD device able to produce large electrical impulses rapidly and repeatedly. Photo by Randy Montoya
The new system, called a linear transformer driver (LTD), was created by researchers at the Institute of High Current Electronics in Tomsk, Russia, in collaboration with colleagues at Sandia.
The circuit — a switch tightly coupled to two capacitors — is about the size of a shoebox and is termed a "brick." When bricks are tightly packed in groups of 20 and electrically connected in parallel in a circular container resembling a large cherry lifesaver, the aggregate, or "cavity" as the physicists would have it, can transmit a current of 0.5 megamperes at 100 kilovolts.
Because the cavities are modular, they can be stacked like donuts on a metal prong called a stalk. Arranged in a suitable configuration, they could generate 60 megamperes and six megavolts of electrical power, enough (theoretically) to generate high-yield nuclear fusion within the parameters necessary to run an electrical power plant.
The next-generation cavity model, now being tested in Tomsk, transmits 1.0 megamperes at the same voltage and with the same rapidity. Five such units have been built; four have been purchased by Sandia, and one by the University of Michigan. The units cost $160,000 each. They too, according to Sandia scientist and project leader Mike Mazarakis, who supervised the tests at the Siberian site, are performing without flaw.
The LTD technology is 50 percent more efficient than current Z machine firings, in terms of the ratio of useful energy out to energy in. Z is currently 15 percent efficient to its load (already a very high efficiency among possible fusion machines).
But fired repeatedly, the machine could well be the fusion machine that could form the basis of an electrical generating plant only two decades away. Progress in this arena might eventually require funding from DOE's energy arm.
To confirm the new Z concept would take $35 million over five to seven years to build a test bed with 100 cavities. If successful, future generations of Z-like facilities would be constructed with LTDs.
Funding thus far has come from two US congressional initiatives through DOE-NNSA Defense Programs, Sandia's internal Laboratory Directed Research and Development monies, and Sandia's Inertial Confinement Fusion program.
"It's like building a tinker toy," says Matzen. "We think we need 60 megamperes to make large fusion yields. But though our simulations show it can be done, we won't know for certain until we actually build it."
Z-pinch has also achieve 2 billion degrees which enables smaller and cleaner fusion plants that can burn helium 3
Metamaterials could boost the power and efficiency of the z-pinch I think the system could approach the performance of a fusion power system and could even transition into being a full fledged fusion power system with a post-ignition z-pinch.
The Z-pinch system is also the basis of the minimag Orion space propulsion concept which could enable travel to Mars in 90 days or less using sub-critical explosions. A full fusion propulsion system would be even more powerful.