Discovering this unexpected combination of current amplification by flux compression and pulse sharpening by a naturally occurring plasma opening switch was a lucky accident
- Edited by Linton Levy -
Prospects for low-cost, clean energy through nuclear fusion just got brighter, thanks to a lucky discovery at Sandia National Laboratories in Albuquerque. A research team led by noted physicist Dr. Franklin Felber has taken a big step towards meeting two of the greatest technological challenges of pulsed power for fusion – current amplification and pulse compression. The team’s discovery was published in Physical Review Letters.
“Discovering this unexpected combination of current amplification by flux compression and pulse sharpening by a naturally occurring plasma opening switch was a lucky accident”
"These are surprising and unexpected results and if confirmed by future experiments could shorten the time scale and lower costs to reach pulsed power-driven nuclear fusion," said Dr. Michael Cuneo, Manager of the Radiation and Fusion Experiments Group at Sandia.
For almost 40 years, research teams around the world have been pursuing energy production by tiny nuclear explosions lasting only billionths of a second within a reactor. This approach, called inertial confinement fusion (ICF), requires that tremendous power be concentrated almost instantaneously onto hydrogen pellets.
The research team had been attempting to boost the power that could be delivered to such fusion targets by fastening small cartridges to Sandia’s enormous Saturn pulsed power generator. The cartridges worked better than hoped, doubling the generator’s current. But the researchers nearly overlooked the results, because the dramatic boost in electrical power occurred unexpectedly, only long after the Saturn generator pulse had ended.
The team theorizes that material heated off the cartridge walls blocked the current pulse, allowing electrical energy to build up inside the cartridge before releasing the energy suddenly into the target volume. Such a means of producing high-power pulses from low-power generators could result in substantial savings in future fusion power plants.
“The work reported here seems to be a significant technological advance in flux compression and opening switches that could potentially accelerate development and reduce capital costs of future fusion power plants,” says Dr. Farhat Beg, Professor of Engineering Physics at the University of California, San Diego, who has been collaborating with Sandia on pulsed power experiments.
In the mid-1980’s, Dr. Felber led a research effort sponsored by the U. S. Department of Energy and including scientists at Sandia and in the former Soviet Union. The team showed that hot ionized gas, called plasma, could ‘pinch’ a magnetic field to what was then the highest value ever produced inside a laboratory, about a hundred million times greater than the Earth’s magnetic field. Since then, research teams around the world have been trying to use this method of plasma ‘magnetic flux compression’ to amplify the high electrical currents needed for fusion.
“The results of these new experiments on the Saturn generator show great promise for the potential of magnetic flux compression to achieve the high electrical powers and short pulses needed for fusion drivers,” says Dr. Alexander Velikovich, Research Physicist at the U.S. Naval Research Laboratory in Washington, D.C., and one of the former Soviet scientists who was a pioneer with Dr. Felber in magnetic flux compression nearly 30 years ago.
For the last 30 years, research teams around the world have also been trying to develop high-power plasma opening switches that could store up electrical energy in a magnetic field and then release the energy suddenly onto a target. The cartridges developed by the research team to amplify currents surprisingly also acted as very effective plasma opening switches, storing up electrical energy for a time much longer than the Saturn generator pulse, and then releasing the energy into the target volume in a time shorter than the Saturn generator pulse.
“Discovering this unexpected combination of current amplification by flux compression and pulse sharpening by a naturally occurring plasma opening switch was a lucky accident,” said Dr. Felber. “I hope these advances are put to use quickly to help solve some of the challenges we face meeting this nation’s power needs in a sustainable manner.”
Starmark, Inc. provides government and corporate clients with advanced research and development services in defense sciences, pulsed power, and homeland security. Since 1987, the company has researched and produced groundbreaking advances for organizations including the U.S. Air Force, the U.S. Marine Corps, the Defense Threat Reduction Agency, the Missile Defense Agency, the National Institutes of Health, and other defense contractors. Starmark employs the work of national laboratories, universities, and other contractors as needed to support its mission of providing the highest quality and most innovative research and development.
During his 35 year career, Dr. Felber has led physics research and development programs for the Army, Navy, Air Force, and Marine Corps, the Defense Advanced Research Projects Agency, the Defense Threat Reduction Agency, the Department of Energy and Department of Transportation, the National Institute of Justice, National Institutes of Health, and national laboratories. Dr. Felber is currently serving as vice president of Starmark, which he co-founded in 1987.
Sandia National Laboratories is a multiprogram laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin, for the U.S. Department of Energy’s National Nuclear Security Administration. With main facilities in Albuquerque, N.M., and Livermore, Calif., Sandia has major R&D responsibilities in national security, energy and environmental technologies, and economic competitiveness.
Anonymous comments will be moderated. Join for free and post now!
What occurs when a jet breaks the sound barrier? Sound waves become more compressed as speed is increased. The compressed sound waves form a V shape on the nose of the plane. When the plane reaches Mach 1 speed a sonic boom can be heard and the aircraft crosses bounded space from subsonic to supersonic. Using the same principal, could energy wave lengths behave similarly under particle beam compression?