Particle Beam Fusion Research

Nuclear Instruments and Methods in Physics Research, 1981

2011

Intense heavy-ion beams have long been considered a promising driver option for inertial-fusion energy production. This paper briefly compares inertial confinement fusion (ICF) to the more-familiar magnetic-confinement approach and presents some advantages of using beams of heavy ions to drive ICF instead of lasers. Key design choices in heavy-ion fusion (HIF) facilities are discussed, particularly the type of accelerator. We

Journal of Fusion Energy, 1991

1999

Vacuum ballistic focusing may be a straightforward method to obtain the heavy ion beam spot size necessary to drive an inertial confinement fusion target. Proper scaling of particle energy, mass, beam current, beam emittance, and magnetic field replicates the dynamics of a full driver beam in a small laboratory experiment. By expanding the beam and then focusing to a very small spot, the effects of aberrations and space charge on this method of final focus can be studied. To date, 200 µA of 120keV K + has been focused to test the matching and focusing elements. A recently designed high brightness contact ionization source is being tested for upcoming focusing measurements with an 87 µA Cs beam that will duplicate the dynamics of a proposed driver design at onetenth scale. Transverse phase space and beam current density at various stages of the focus will be presented. Follow-on measurements studying electron neutralization of space charge and its effect on the focus will be explored.

Science, 1986

PACS2001. Proceedings of the 2001 Particle Accelerator Conference (Cat. No.01CH37268), 2001

The promise of inertial fusion energy driven by heavy ion beams requires the development of accelerators that produce ion currents (~100's Amperes/beam) and ion energies (~1 -10 GeV) that have not been achieved simultaneously in any existing accelerator. The high currents imply high generalized perveances, large tune depressions, and high space charge potentials of the beam center relative to the beam pipe. Many of the scientific issues associated with ion beams of high perveance and large tune depression have been addressed over the last two decades on scaled experiments at

Journal de Physique IV (Proceedings), 2006

Key scientific results from recent experiments, modeling tools, and heavy ion accelerator research are summarized that explore ways to investigate the properties of high energy density matter in heavy-ion-driven targets, in particular, strongly-coupled plasmas at 0.01 to 0.1 times solid density for studies of warm dense matter, which is a frontier area in high energy density physics. Pursuit of these near-term objectives has resulted in many innovations that will ultimately benefit heavy ion inertial fusion energy. These include: neutralized ion beam compression and focusing, which hold the promise of greatly improving the stage between the accelerator and the target chamber in a fusion power plant; and the Pulse Line Ion Accelerator (PLIA), which may lead to compact, low-cost modular linac drivers.

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2005

Research during the past decade has strongly increased our confidence that the heavy ion accelerator is the superior driver candidate for economic power ge neration by inertial confinement fusion. The European Community nonetheless concentrates nearly all its fusion re search spending on thermonuclear fusion using magnetic confinement techniques. Results achieved with high intensity laser beams and systematic theoretical studies have provided the necessary reference data for implosion of a fuel pellet, the most crucial issue in inertial confinement fusion. With respect to the conditions for ignition and continuous burning, experi ments with laser beams are about as close to break-even as those using magnetic confinement. For example, a 20 kJ beam at the NOVA facility at Livermore in the USA has obtained 150 times liquid density for the deuterium (D)-tritium (T) fuel mix, while Japan's GEKKO XII laser facility has achieved a compression factor of 600. Experimental results for pellet implosions in underground nuclear explosions con firm theoretical predictions that a pulse energy of about 5 MJ is necessary for implosion. Unfortunately, laser facilities as drivers, while indispensible for future target re search, have serious shortcomings for electricity generating power plant, notably low efficiencies and repetition rates such that it is hard to imagine how the neces sary orders of magnitude improvements could be obtained to meet commercial requirements. The principle alternatives are heavy ion accelerators as both the effi ciency and the repetition rate are not criti cal and other requirements such as final focussing and beam-target coupling ap pear satisfactory. Enormous progress in accelerator technology and experience with operational reliability at complex accelerator facilities also place heavy ion drivers in a favourable light noting, of course, that the required beam intensities exceed by a wide margin those of existing accelerators. In view of the progress, our aim here is to review the development of heavy ion drivers for inertial confinement fusion and consider some perspectives.

Physics of Plasmas, 2008

Issues with coupling efficiency, beam illumination symmetry, and Rayleigh-Taylor instability are discussed for spherical heavy-ion-beam-driven targets with and without hohlraums. Efficient coupling of heavy-ion beams to compress direct-drive inertial fusion targets without hohlraums is found to require ion range increasing several-fold during the drive pulse. One-dimensional implosion calculations using the LASNEX inertial confinement fusion target physics code shows the ion range increasing fourfold during the drive pulse to keep ion energy deposition following closely behind the imploding ablation front, resulting in high coupling efficiencies ͑shell kinetic energy/ incident beam energy of 16% to 18%͒. Ways to increase beam ion range while mitigating Rayleigh-Taylor instabilities are discussed for future work.

19Th Particle Accelerator Conference, 2001

The promise of inertial fusion energy driven by heavy ion beams requires the development of accelerators that produce ion currents (~100's Amperes/beam) and ion energies (~1 -10 GeV) that have not been achieved simultaneously in any existing accelerator. The high currents imply high generalized perveances, large tune depressions, and high space charge potentials of the beam center relative to the beam pipe. Many of the scientific issues associated with ion beams of high perveance and large tune depression have been addressed over the last two decades on scaled experiments at

Proceedings of the 1997 Particle Accelerator Conference (Cat. No.97CH36167), 2000

Transverse beam combining is a cost-saving option employed in many designs for induction linac heavy ion fusion drivers. The resultant transverse emittance increase, due predominantly to anharmonic space charge forces, must be kept minimal so that the beam remains focusable at the target. A prototype combining experiment has been built and preliminary results are presented. Four sources each produce up to 4.8 mA Cs + beams at 160 keV. Focusing upstream of the merge consists of four quadrupoles and a final combined-function element (quadrupole & dipole). All lattice elements of the prototype are electrostatic. Due to the small distance between beams near the merge (~ 3-4 mm), the electrodes here are a cage of small rods, each at different voltage.

2011

• Extend validation of beam acceleration and focusing at high current, and for multiple beams. Continue source-through-target simulation studies for each step toward a power plant system. • Optimize target design to minimize required driver cost and beam focusing requirements. • Work with industry to further develop and reduce the cost of custom accelerator components. • Contribute to and learn from fusion, plasma, and accelerator science and technology. • The DOE/SC/FES program on ion-heated HEDLP / Warm Dense Matter physics. • The research programs in heavy ion fusion and related areas, in Europe, Russia, and Japan. • The large worldwide research programs in accelerators for a broad range of applications. • The ICF program in targets; the MFE program (esp. work on plasma simulation and magnets). • The high-perveance beam physics experiments at U. MD (UMER) and Princeton (PTSX). • The pulsed power fusion program, particularly for chamber protection and power handling. • Experimental demonstration of: focusing to mm-scale spots; beam merging for a compact

Nuclear Fusion

Significant experimental and theoretical progress has been made in the U.S. heavy ion fusion program on high-current sources, injectors, transport, final focusing, chambers and targets for high energy density physics (HEDP) and inertial fusion energy (IFE) driven by induction linac accelerators. One focus of present research is the beam physics associated with quadrupole focusing of intense, space-charge dominated heavy-ion beams, including gas and electron cloud effects at high currents, and the study of long-distance-propagation effects such as emittance growth due to field errors in scaled experiments. A second area of emphasis in present research is the introduction of background plasma to neutralize the space charge of intense heavy ion beams and assist in focusing the beams to a small spot size. In the near future, research will continue in the above areas, and a new area of emphasis will be to explore the physics of neutralized beam compression and focusing to high intensities required to heat targets to high energy density conditions as well as for inertial fusion energy.

Soviet Atomic Energy, 1978

The second conference, held in October 1977 at Ithaca (U.S.A.), was attended by 206 delegates from the U.S.A., the USSR, France, Israel, Japan, Great Britain, the Netherlands, and the Federal Republic Germany. A total of 74 papers were presented on the following topics, Investigation of Temperature Signaling Devices with Inertial Plasma Retention in the Case of Target Heating by Electron and Ion Beams

Fusion Technology, 1997

Résumé/Abstract The present state of the art concerning the use of intense cluster ion beams for driving an inertial fusion pellet containing a thermonuclear fuel is reviewed. Emphasis is placed on the fragmentation and stopping of correlated ion fragments in ...