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Artist's conception of a heavy ion fusion power plantArtist's conception of an IFE powerplant

We further inertial fusion energy as a future power source, primarily through R&D on heavy-ion induction accelerators. Our program collaborates closely with Lawrence Livermore National Laboratory and the Princeton Plasma Physics Laboratory in close collaboration on inertial fusion driven by beams of heavy ions. The related emergent science of high-energy-density physics (HEDP) has become a major focus.

For further synergy, we have combined forces with the Ion Beam Technology Program.

Fusion and IBT in the News: The Ion Beam Technology Program recently shared the R&D 100 award for the "High Output Neutron Generator" by Adelphi Technology, Inc. The neutron production process begins with a plasma ion source whose development was led by Bernhard Ludewigt and Qing Ji of IBT. It is the 13th of these "Oscars of Innovation" that IBT and its predecessor programs in magnetic fusion energy and Bevalac operations have figured into since their first victory in 1985.

The accelerator NDCX-II and its uses are the subjects of "A New Accelerator to Study Steps on the Path to Fusion", a feature article by Berkeley Lab's public information department. It follows up on earlier stories about NDCX-II and about the role of computer simulation in NDCX-II (a key theme in accelerator design today).

André Anders of the Ion Beam Technology group was presented the 2010 Merit Award for "outstanding technical contributions" by the IEEE Nuclear and Plasma Sciences Society. He also led the team that won an R&D 100 last year.

The Why and How of Inertial Fusion Energy

As the world contemplates dwindling fossil-fuel supplies and the environmental costs of energy production, fusion looks ever more appealing. The fuel (hydrogen isotopes called deuterium and tritium) can be readily obtained, and the reactions do not create the large long-lived radioactive waste stream associated with fission. However, controlled fusion on a power-plant scale will require years of further development; typical estimates call for a demonstration power plant to begin operation in two or three decades.

The DOE supports two approaches to controlled fusion. One is based on magnetic confinement, with large "magnetic bottles" such as tokamaks. The other uses inertial confinement, in which a small capsule of fusion fuel is heated and compressed, so that the fusion reaction take place before the fuel flies apart. A large program, supported by the DOE's National Nuclear Security Agency, is studying the basic physics of the inertial approach, using large lasers as "drivers."

LBNL's Fusion Energy program is part of a smaller effort, supported by the DOE's Office of Science, to harness inertial fusion energy for electric power production in an approach known as Heavy Ion Fusion. In this approach, powerful and energetic beams of heavy ions are focused by magnetic lenses outside the target chamber to concentrate them on the target. The goal is for the targets to yield much more energy than was put into them by the beams. This is explained in detail by a tutorial at the Program's own website.

Our program has the long-range goal of developing suitable heavy-ion accelerators that will not only "drive" a fusion target, but also have cost, efficiency, and reliability that make business sense as the basis for a power plant. Since our beginnings in 1982, we have been progressively scaling up induction accelerator systems that transport beams and give them more energy.

e are now working on a new generation of experiments that also serve the emerging science of high energy density physics (HEDP), as described below.

NDCX-II: The Next Step for Heavy-Ion Fusion and HEDP

With the added support of the American Recovery and Reinvestment Act, we have built an accelerator called the Neutralized Drift Compression Experiment II. NDCX-II and its uses are the subjects of "A New Accelerator to Study Steps on the Path to Fusion", a feature article by Berkeley Lab's public information department. For more information on the uses of NDCX-II, see this article, circa the beginning of the project. Using the new machine's hundredfold increase in energy compared to NDCX-I, we will explore how the range across which the ions deposit their energy can be tailored (via ramped or double pulses) to optimize hydrodynamic coupling in direct-drive targets. Experiments with ramped and double pulses can be accommodated. This work will help explore HEDP and also move us forward on the long-term fusion roadmap.

This R&D is synergistic with planned experiments at the National Ignition Facility, the world's most powerful laser, which was commissioned at LLNL in May 2009. Ignition (efficient fusion) in laser IFE targets, and validation of capsule gain (ratio of fusion energy output to beam energy input) and capsule hydro-coupling efficiency, are expected to increase enthusiasm for the end product of our work. That eventual end product will be heavy-ion accelerators that will “drive” IFE in a technically and economically attractive power plant, along with targets and other elements required for such a system.

The emergent science of high-energy-density physics with laboratory plasmas (HEDP-LP), a topic closely related to IFE target physics, has come to play a large role in our program. Some key aspects of HEDP—dubbed “the X Games of contemporary science” by a National Research Council committee—are a natural match for the experimental facilities, modeling techniques, and areas of expertise of the VNL. In 2008 we performed the first target experiment in the Warm Dense Matter regime of HEDP, using beams of K (potassium with a single positive charge) ions from NDCX-I. Experiments continue, and will get a tremendous boost from NDCX-II, which will provide much more energy — of order 0.1 to 0.14 joules of lithium (Li) ions at kinetic energies exceeding 3 MeV— at the target, while alongside it, NDCX-I continues to serve HEDP users.