FESP’s HEDLP and IFE science research with ion beams is carried out in collaboration with Heavy Ion Fusion Science Virtual National Laboratory (HIFS-VNL) partners Lawrence Berkeley National Laboratory (LBNL) and Princeton Plasma Physics laboratory (PPPL). Areas of research include:
- Heavy Ion Fusion for IFE
- Warm Dense Matter (WDM) and HIF target-physics studies
- Intense ion beam and plasma physics
What the HIFS-VNL partners study …
- Heavy-Ion Fusion (HIF)
Accelerators represent an attractive driver option for Inertial Fusion Energy. They have long lifetimes, deliver repetition rates in the multiple-Hertz regime or higher, and have an efficiency that is high enough to allow use of indirect-drive targets (such as those to be tested soon on NIF) while still attaining a usable system gain. Beams entering HIF fusion chambers are focused by magnetic fields, making the system robust to the effects of target explosions, and the chamber wall can be protected by a neutronically-thick flowing liquid, minimizing “first wall” issues. In addition to conceptual designs with indirect-drive targets, we have recently initiated studies of novel “ion drive” targets, which may offer high gain at low driver energy, and "ion ignition" targets, which compress the fuel, perhaps using a single-sided illumination geometry, then ignite it with a short-pulse ion beam.
- Physics of Warm Dense Matter (WDM) and HIF targets
The HIFS-VNL is using experiments, analytic theory, and computer simulations to study the basic physics of matter heated rapidly by ion beams. Ion stopping can be well-characterized and offers uniform energy deposition throughout a sample volume. Using the Neutralized Drift Compression eXperiment (NDCX) facility at LBNL, we are studying the behavior of heated metal foils in an attempt to better understand such topics as droplet formation and material properties in the two-phase region of the density-temperature phase space. Construction is underway of a higher-energy facility, NDCX-II, which reuses components from LLNL’s decommissioned ATA accelerator, and will be completed in 2012. See "Experimental Facilities at LBNL," below, and a HIFS-VNL news item about the project. An “Integrated Beam - High Energy Density Physics eXperiment”, the next logical step beyond NDCX-II, has received Critical Decision Zero (mission need) approval from DOE.
- Intense ion beam and plasma physics
A long-term focus of the HIFS-VNL has been developing ion accelerators that can repeatedly deliver very high ion currents (~kA / beam) at moderate energies (~1-10 GeV) onto fusion targets. This focus has led to pioneering work in the experimental study, analysis and simulation of “space charge dominated” beams. The High-Current Experiment (HCX) used a "driver-scale" heavy-ion beam to make valuable contributions to the understanding of beam halo, electron-cloud effects, and maximum transportable current. More recently, the WDM mission introduced new demands for ns-scale pulses at low kinetic energies (a few MeV) near the Bragg deposition peak. To attain these goals, we invented "neutralized drift compression," an ion analogue of chirped-pulse amplification in lasers. We give the tail on an ion beam a higher velocity than the head, then allow the beam to compress in a plasma environment which neutralizes the space charge that otherwise would limit compression. We have measured compression factors on NDCX exceeding 50x, and even better performance is expected from NDCX-II. We are exploring the application of this technique to the HIF mission as well. Computer simulations play an essential role in this work and have necessarily required development of new methods and sophisticated codes. See "Warp code simulation and NDCX experimental data," below, and a HIFS-VNL news item about our simulation work.
Experimental Facilities at LBNL
LLNL Employees in the HIFS-VNL
John Barnard (HIFS-VNL Deputy Director) - Warm Dense Matter theory and simulation, beam theory
Alex Friedman (VNL Theory / Simulations Group leader) - beams & plasmas, NDCX-II physics
Dave Grote - Warp code and experimental support
Steve Lund - fundamental theory and experimental support
Bill Sharp - NDCX-II physics
Ron Cohen - theory, algorithm development, experimental support (40% time)
John Perkins – Inertial Fusion Energy target design
Matt Terry – Inertial Fusion Energy target design and NDCX-II experiment design
Art Molvik (LLNL Retiree) - experimental plasma and beam physics, electron cloud diagnosis and cure
Dick More (ex-LLNL Division Leader) - Warm Dense Matter theory, atomic physics, expt’l support
Dick Briggs (ex-LLNL Beam Research AD) - accelerators, particle beams, and plasma physics
Martin Campos Pinto (Fulbright scholar, France) – novel numerical methods using adaptive particles
Students working with LLNL HIFS-VNL staff at LBNL (current and recent)
Frank Nürnberg - TU Darmstadt (Markus Roth) and GSI - capturing ions made by lasers hitting foils
Jakob Runge - Fulbright from HU Berlin - ion direct drive illumination geometries
Julien Armijo - Institute d'Optique, France - WDM droplet evolution physics
Siu-fai Ng - Chinese U. of Hong Kong - hydrodynamic modeling of NDCX II WDM and IFE experiments
Michael Hay - UCB undergraduate/Princeton graduate student - hydro simulations of ion direct drive using HYDRA
Alex Zylstra - Pomona undergraduate/MIT graduate student - hydro simulations of ion heated metallic foams
Guy Parsey - UC Santa Barbara undergraduate - theory of beam transport
Guillaume Bazouin - Grenoble INP Phelma - theoretical and experimental beam transport
Warp code simulation and NDCX experimental data
To learn more...
The 17th International Symposium on Heavy Ion Inertial Fusion took place in Tokyo, August 2008. For the agenda, click here.
For the HIFS-VNL talks and papers, click here.
The 18th International Symposium on Heavy Ion Inertial Fusion was held in Darmstadt, Germany 28 August – 2 September 2010. For the conference website, click here. The HIFS-VNL talks are posted here.
The 19th International Symposium on Heavy Ion Inertial Fusion was held in Berkeley, California, August 12-17, 2012. For the conference website click here. The agenda and talks may be found here.
Heavy Ion Fusion Science Virtual National Laboratory
The Heavy Ion Fusion Science Virtual National Laboratory is a collaboration of LLNL, Lawrence Berkeley National Laboratory, and the Princeton Plasma Physics Laboratory. The LLNL group is part of the Fusion Energy Sciences Program within the Physics Division of the Physical and Life Sciences Directorate. Our principal funding is from the DOE Office of Fusion Energy Sciences (OFES) program in High Energy Density Laboratory Plasmas (HEDLP) and related topics. Most of the group members maintain their principal offices at LBNL.