The Pursuit of Fusion Energy
FUSION research has been an integral component of Lawrence Livermore’s science and technology portfolio from the very beginning. In 2001, the Magnetic Fusion Energy and Inertial Fusion Energy programs were combined to form the Fusion Energy Program (FEP) in the Physics and Advanced Technologies Directorate. Researchers from this program have a long history of involvement in the exploration of magnetic fusion plasma confinement concepts. As described in the article A Dynamo of a Plasma, Livermore’s Sustained Spheromak Physics Experiment (SSPX) is the latest of these concepts to be explored.
SSPX research is funded through the Department of Energy’s (DOE’s) Office of Fusion Energy Sciences to study the physics of plasma configurations with the potential to greatly affect future magnetic fusion energy development. SSPX research has led to more than 35 journal papers, including six in Physical Review Letters. SSPX researchers have been invited to present their work at national and international fusion conferences. Recently, Livermore joined with the University of Wisconsin, the University of Chicago, and others to form the National Science Foundation’s Frontier Science Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas. Through interactions with this center, SSPX experiments and theory contribute to our growing understanding of how some of the largest astrophysical objects form.
Scientists from Livermore’s FEP are also conducting research on two other magnetic fusion experiments, the DIII-D tokamak at General Atomics in San Diego, California, and the National Spherical Torus Experiment at Princeton University’s Plasma Physics Laboratory. Recently, an international agreement was signed to begin construction of the International Thermonuclear Experimental Reactor (ITER), a large tokamak designed to produce 500 megawatts of fusion power. Magnetic fusion researchers at the Laboratory have been participating in the ITER project since its inception. Livermore scientists working at DIII-D have led the effort to develop new methods for reducing the heat load on the walls of ITER and are developing plasma diagnostics that the U.S. will install on ITER once it is operational.
In parallel with joining the ITER construction project, the U.S. fusion energy community has initiated a new effort, the Fusion Simulation Project, to significantly improve capabilities for simulating tokamak fusion plasmas. Numerical simulation of a magnetically confined fusion plasma is a grand scientific challenge at the forefront of computational physics. The FEP’s theory group, building on the success of a Laboratory Directed Research and Development project, recently won a DOE competition to begin work on the Fusion Simulation Project. Livermore scientists will focus on understanding how tokamak plasmas spontaneously form insulating surface layers where plasma temperatures drop from more than 40 million degrees to a few thousand over a distance of just a few centimeters.
Research on inertial fusion, in which the plasma is confined by laser-driven energy fields rather than by magnetic fields, is also moving forward in exciting new directions. Historically, Livermore has been involved in all aspects of inertial fusion energy research and development, including target physics, laser and heavy-ion drivers, and fusion chambers. To address key issues and developmental needs for inertial fusion energy, FEP personnel work closely with colleagues in the National Ignition Facility (NIF) Programs, Defense and Nuclear Technologies, and Engineering directorates as well as with researchers from other national laboratories, universities, and industry. Currently, the focus of this research is on laser-driven inertial fusion—part of a coordinated national effort known as the High Average Power Laser Program—and fast ignition, an alternative to conventional hot-spot ignition that has the potential for high target gain with less driver energy. In addition, Livermore participates in the national Heavy-Ion Fusion Program, which aims to achieve very intense beams for basic physics research, such as high-energy-density physics. These results will also benefit the heavy-ion approach to inertial fusion energy. All of these programs offer opportunities to explore physics and advanced technologies that are at the forefront of international efforts.
The pursuit of fusion energy is an endeavor rich in scientific and technological challenges, with the potential to yield tremendous benefits to energy security, economic competitiveness, and international stability. As such, fusion research has always been an attractive field for young, talented scientists and engineers. Many key science and engineering leaders at Livermore have been associated with magnetic fusion research and projects at some point in their careers. The prospect of lighting the fusion fire at NIF and ITER portends an exciting future for fusion research at Livermore.