Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

NIF experiments show initial gain in fusion fuel

13.02.2014
Ignition -- the process of releasing fusion energy equal to or greater than the amount of energy used to confine the fuel -- has long been considered the "holy grail" of inertial confinement fusion science.

A key step along the path to ignition is to have "fuel gains" greater than unity, where the energy generated through fusion reactions exceeds the amount of energy deposited into the fusion fuel.


A metallic case called a hohlraum holds the fuel capsule for NIF experiments. Target handling systems precisely position the target and freeze it to cryogenic temperatures (18 kelvins, or -427 degrees Fahrenheit) so that a fusion reaction is more easily achieved. Photo by Eduard Dewald/LLNL

Though ignition remains the ultimate goal, the milestone of achieving fuel gains greater than 1 has been reached for the first time ever on any facility. In a paper published in the Feb. 12 online issue of the journal Nature, scientists at Lawrence Livermore National Laboratory (LLNL) detail a series of experiments on the National Ignition Facility (NIF), which show an order of magnitude improvement in yield performance over past experiments.

"What's really exciting is that we are seeing a steadily increasing contribution to the yield coming from the boot-strapping process we call alpha-particle self-heating as we push the implosion a little harder each time," said lead author Omar Hurricane.

Boot-strapping results when alpha particles, helium nuclei produced in the deuterium-tritium (DT) fusion process, deposit their energy in the DT fuel, rather than escaping. The alpha particles further heat the fuel, increasing the rate of fusion reactions, thus producing more alpha particles. This feedback process is the mechanism that leads to ignition. As reported in Nature, the boot-strapping process has been demonstrated in a series of experiments in which the fusion yield has been systematically increased by more than a factor of 10 over previous approaches.

The experimental series was carefully designed to avoid breakup of the plastic shell that surrounds and confines the DT fuel as it is compressed. It was hypothesized that the breakup was the source of degraded fusion yields observed in previous experiments. By modifying the laser pulse used to compress the fuel, the instability that causes break-up was suppressed. The higher yields that were obtained affirmed the hypothesis, and demonstrated the onset of boot-strapping.

The experimental results have matched computer simulations much better than previous experiments, providing an important benchmark for the models used to predict the behavior of matter under conditions similar to those generated during a nuclear explosion, a primary goal for the NIF.

The chief mission of NIF is to provide experimental insight and data for the National Nuclear Security Administration's science-based Stockpile Stewardship Program. This experiment represents an important milestone in the continuing demonstration that the stockpile can be kept safe, secure and reliable without a return to nuclear testing. Ignition physics and performance also play a key role in fundamental science, and for potential energy applications.

"There is more work to do and physics problems that need to be addressed before we get to the end," said Hurricane, "but our team is working to address all the challenges, and that's what a scientific team thrives on."

Hurricane is joined by co-authors Debbie Callahan, Daniel Casey, Peter Celliers, Charlie Cerjan, Eduard Dewald, Thomas Dittrich, Tilo Doeppner, Denise Hinkel, Laura Berzak Hopkins, Sebastien Le Pape, Tammy Ma, Andrew MacPhee, Jose Milovich, Arthur Pak, Hye-Sook Park, Prav Patel, Bruce Remington, Jay Salmonson, Paul Springer and Riccardo Tommasini of LLNL, and John Kline of Los Alamos National Laboratory.

More Information

"Design of a High-Foot High-Adiabat ICF Capsule for the National Ignition Facility," Physical Review Letters, Feb. 7, 2014

"High-Adiabat High-Foot Inertial Confinement Fusion Implosion Experiments on the National Ignition Facility," Physical Review Letters, Feb. 7, 2014

"Encouraging Signs on the Path to Fusion," American Physical Society Viewpoint, Feb. 5, 2014

National Ignition Facility

"Laser fusion experiment yields record energy," LLNL news release, Aug. 26, 2013

Founded in 1952, Lawrence Livermore National Laboratory provides solutions to our nation's most important national security challenges through innovative science, engineering and technology. Lawrence Livermore National Laboratory is managed by Lawrence Livermore National Security, LLC for the U.S. Department of Energy's National Nuclear Security Administration.

Breanna Bishop | EurekAlert!
Further information:
http://www.llnl.gov

More articles from Power and Electrical Engineering:

nachricht New welding process joins dissimilar sheets better
28.09.2016 | Technologie Lizenz-Büro (TLB) der Baden-Württembergischen Hochschulen GmbH

nachricht Cooling buildings with solar heat
26.09.2016 | FIZ Karlsruhe – Leibniz-Institut für Informationsinfrastruktur GmbH

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First-Ever 3D Printed Excavator Project Advances Large-Scale Additive Manufacturing R&D

Heavy construction machinery is the focus of Oak Ridge National Laboratory’s latest advance in additive manufacturing research. With industry partners and university students, ORNL researchers are designing and producing the world’s first 3D printed excavator, a prototype that will leverage large-scale AM technologies and explore the feasibility of printing with metal alloys.

Increasing the size and speed of metal-based 3D printing techniques, using low-cost alloys like steel and aluminum, could create new industrial applications...

Im Focus: New welding process joins dissimilar sheets better

Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of light metals.
Scientists at the University of Stuttgart have now developed two new process variants that will considerably expand the areas of application for friction stir welding.
Technologie-Lizenz-Büro (TLB) GmbH supports the University of Stuttgart in patenting and marketing its innovations.

Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of...

Im Focus: First quantum photonic circuit with electrically driven light source

Optical quantum computers can revolutionize computer technology. A team of researchers led by scientists from Münster University and KIT now succeeded in putting a quantum optical experimental set-up onto a chip. In doing so, they have met one of the requirements for making it possible to use photonic circuits for optical quantum computers.

Optical quantum computers are what people are pinning their hopes on for tomorrow’s computer technology – whether for tap-proof data encryption, ultrafast...

Im Focus: OLED microdisplays in data glasses for improved human-machine interaction

The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.

“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...

Im Focus: Artificial Intelligence Helps in the Discovery of New Materials

With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.

Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Paper – Panacea Green Infrastructure?

30.09.2016 | Event News

HLF: From an experiment to an establishment

29.09.2016 | Event News

European Health Forum Gastein 2016 kicks off today

28.09.2016 | Event News

 
Latest News

First-Ever 3D Printed Excavator Project Advances Large-Scale Additive Manufacturing R&D

30.09.2016 | Materials Sciences

New Technique for Finding Weakness in Earth’s Crust

30.09.2016 | Earth Sciences

Cells migrate collectively by intermittent bursts of activity

30.09.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>