Max Tabak

• Doctor of Philosophy
• Lawrence Livermore National Laboratory

This paper presents a “hybrid” approach to direct drive inertial confinement fusion that can exploit a high-energy gas laser with two opposed beams. The target and driver are asymmetric, much like experiments performed on the National Ignition Facility, but have been designed to benefit from scale and their particular compatibility with a fusion po...

We present particle-in-cell simulations with Monte Carlo collisions of fusion burn waves in compressed deuterium–tritium and proton–boron plasmas. We study the energy balance in the one-dimensional expansion of a hot-spot by simulating Coulomb collisions, fusion reactions, and bremsstrahlung emission with a Monte Carlo model and inverse bremsstrahl...

The development of advanced targets capable of achieving ignition with improved energy gain at lower driver energies is one of four key technical challenges to be solved in order to realize economical inertial fusion energy. We report the minimum energy necessary for a small hemispherical mass of fast-ignited high-density deuterium–tritium fuel to...

We assess the conversion efficiency from intense picosecond laser pulses to multi-MeV ion beams for a wide range of laser and target parameters, using 2D kinetic particle-in-cell simulations. Scalings are addressed in a quasi-one-dimensional geometry, leaving out beam divergence. Then, we study the conversion efficiency into a narrow spatial band a...

On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain G target of 1.5. This is the first laboratory demonstration of exceeding “scientific breakeven” (or G target > 1 ) where 2.05 MJ of 351 nm laser light produced 3.1 MJ of total fusion yield, a result which significantly exceeds the...

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a...

The very short burn time and small size of burning plasmas created at advanced laser-fusion facilities will require high-spatial-resolution imaging diagnostics with fast time resolution. These instruments will need to function in an environment of extremely large neutron fluxes that will cause conventional diagnostics to fail because of radiation d...

In indirect drive inertial confinement fusion (ICF), laser induced Hohlraum preheat radiation (so-called M-band, >1.8 keV) asymmetry will lead to asymmetric ablation front and ablator–fuel interface hydrodynamic instability growth in an imploding capsule. First experiments to infer the M-band asymmetries at the capsule were performed on the Nationa...

This paper analyzes x-ray-driven implosions that are designed to be less sensitive to 2D and 3D effects in Hohlraum and capsule physics. Key performance metrics including the burn-averaged ion temperature, hot-spot areal density, and fusion yield are found to agree with simulations where the design adiabat (internal pressure) is multiplied by a fac...

The shaping of the drive pulse in time is a key tool in the design of fusion experiments that use inertia to confine burning plasmas. It is directly related to the adiabat and compressibility of the DT fuel and the characteristics of the laser and target that are needed to ignite. With this in mind, we have performed experiments at the National Ign...

Progress in inertial confinement fusion depends on the accurate interpretation of experiments that are complex and difficult to explain with simulations. Results could depend on small changes in the laser pulse or target or physics that are not fully understood or characterized. In this paper, we discuss an x-ray-driven platform [Baker et al., Phys...

A target design for mitigating the Rayleigh-Taylor instability is proposed for use in high energy density and direct-drive inertial confinement fusion experiments. In this scheme, a thin gold membrane is offset from the main target by several-hundred microns. A strong picket on the drive beams is incident upon this membrane to produce x rays which...

New short-pulse kilojoule, Petawatt-class lasers, which have recently come online and are coupled to large-scale, many-beam long-pulse facilities, undoubtedly serve as very exciting tools to capture transformational science opportunities in high energy density physics. These short-pulse lasers also happen to reside in a unique laser regime: very hi...

Multiple laser-entrance-hole (LEH) designs are proposed which increase the number of LEHs, n, from two in standard designs. This is done to minimize the laser travel distance in the hohlraum and to obtain algebraically vanishing low order radiation moments, thereby allowing smaller case-to-capsule ratios. This leads to higher coupling efficiencies...

Plasma amplifiers offer a route to side-step limitations on chirped pulse amplification and generate laser pulses at the power frontier. They compress long pulses by transferring energy to a shorter pulse via the Raman or Brillouin instabilities. We present an extensive kinetic numerical study of the three-dimensional parameter space for the Raman...

Raman and Brillouin amplification are two schemes for amplifying and compressing short laser pulses in plasma. Analytical models have already been derived for both schemes, but the full consequences of these models are little known or used. Here, we present new criteria that govern the evolution of the attractor solution for the seed pulse in Raman...

Absorption covers the physical processes which convert intense photon flux into energetic particles when a high-power laser illuminates optically-thick matter. It underpins important petawatt-scale applications today, e.g., medical-quality proton beam production. However, development of ultra-high-field applications has been hindered since no study...

The interaction of petawatt (10(15) W) lasers with solid matter forms the basis for advanced scientific applications such as table-top particle accelerators, ultrafast imaging systems and laser fusion. Key metrics for these applications relate to absorption, yet conditions in this regime are so nonlinear that it is often impossible to know the frac...

This paper presents a short overview of a series of review articles describing alternative approaches to ignition of fusion reactions in inertially confined plasmas.

Integrated fast ignition experiments were performed at ILE, Osaka, and LLE, Rochester, in which a nanosecond driver laser implodes a deuterated plastic shell in front of the tip of a hollow metal cone and an intense ultrashort-pulse laser is injected through the cone to heat the compressed plasma. Based on the initial successful results of fast ele...

We derive upper and lower bounds on the absorption of ultraintense laser light by solids as a function of fundamental laser and plasma parameters. These limits emerge naturally from constrained optimization techniques applied to a generalization of the laser-solid interaction as a strongly-driven, relativistic, two degree of freedom Maxwell-Vlasov...

Particle coupling to the oscillatory and steady-state nonlinear force of an ultraintense laser is studied through analytic modeling and particle-in-cell simulations. The complex interplay between these absorption mechanisms--corresponding, respectively, to ``hot'' electrons and ``hole punching'' ions--is central to the viability of many ultraintens...

The energy and angular distributions of the fast electrons predicted by particle-in-cell (PIC) simulations differ from those historically assumed in ignition designs of the fast ignition scheme. Using a particular 3D PIC calculation, we show how the ignition energy varies as a function of source-fuel distance, source size, and density of the pre-co...

We report on progress in the design of a high gain fast ignition (FI) target using an integrated suite of codes capable of simulating all aspects of an FI implosion. Integrated hohlraum and capsule simulations are performed with the radiation-hydrodynamics code, HYDRA. The ultrashort-pulse laser-plasma interaction and fast electron generation is si...

We present a methodology for conducting the design calculations for fast ignition indirect-drive implosions with an embedded cone for introducing a second laser beam to ignite the compressed fuel. These calculations are tuned to achieve several design goals. We demonstrate a major feature of the implosion simulations, the lagging of the implosions...

Transport modeling of idealized, cone-guided fast ignition targets indicates the severe challenge posed by fast-electron source divergence. The hybrid particle-in-cell (PIC) code Zuma is run in tandem with the radiation-hydrodynamics code Hydra to model fast-electron propagation, fuel heating, and thermonuclear burn. The fast electron source is bas...

Transport modeling of idealized, cone-guided fast ignition targets indicates the severe challenge posed by fast-electron source divergence. The hybrid particle-in-cell [PIC] code Zuma is run in tandem with the radiation-hydrodynamics code Hydra to model fast-electron propagation, fuel heating, and thermonuclear burn. The fast electron source is bas...

A method for producing a self-generated magnetic focussing structure for a beam of laser-generated relativistic electrons using a complex array of resistivity gradients is proposed and demonstrated using numerical simulations. The array of resistivity gradients is created by using a target consisting of alternating layers of different Z material. T...

Simulations of ignition-scale fast ignition targets have been performed with the new integrated Zuma-Hydra PIC-hydrodynamic capability. We consider an idealized spherical DT fuel assembly with a carbon cone, and an artificially-collimated fast electron source. We study the role of E and B fields and the fast electron energy spectrum. For mono-energ...

The number of e-foldings for the classical Rayleigh-Taylor instability is linear in the velocity change. The required velocity change is set by fusion ignition conditions. However, the number of e-foldings is influenced by how fast this velocity change can be obtained. Shorter acceleration distances result in a lower number of e-foldings. For fixed...

Dry-wall IFE designs such as LIFE utilize Xe fill gas to protect the target chamber first wall from x-ray heating and ionic debris. A key question is how cool, settled and clean the Xe must be to permit beam propagation and target transport, and how to reach this state at a 10+ Hz shot repetition rate. Xe is at low density in the target chamber, an...

The fast ignition (FI) approach to inertial confinement fusion offers the potential for achieving the high target gains required for Inertial Fusion Energy (IFE). This paper reports progress at LLNL on the development of a point design for an indirect-drive re-entrant-cone FI target. Integrated hohlraum and capsule designs are described that optimi...

We discuss three schemes that can improve the coupling of short pulse laser generated hot electrons to the fuel. First, we extend the ideas of A. Robinson, et.al., where azimuthal B fields are grown where there are gradients in resistivity. We utilize higher-Z materials where the material temperature can be kept low and resistivity gradients high b...

IFE target designers must consider several engineering requirements in addition to the physics requirements for successful target implosion. These considerations include low target cost, high manufacturing throughput, the ability of the target to survive the injection into the fusion chamber and arrive in a condition and physical position consisten...

The Laser Inertial Fusion Energy (LIFE) concept is being designed to operate as either a pure fusion or hybrid fusion-fission system. The present work focuses on the pure fusion option. A key component of a LIFE engine is the fusion chamber subsystem. It must absorb the fusion energy, produce fusion fuel to replace that burned in previous targets,...

Coupling highly divergent electron beams to the fuel in Fast Ignition designs will require putting the critical surface where the electrons are born close to the high fuel density region and creating magnetic structures that can guide the flows of relativistic electrons. We use asymmetric implosions to protect the cone tip from a high pressure jet...

We perform electron-beam transport simulations with the LSP code [D. R. Welch et al., Phys. Plasmas 13, 063105 (2006)] to determine the ignition requirements for cone-guided fast ignition. We run LSP as a direct-implicit PIC code, with a fluid treatment of the dense background. We use idealized plasma conditions for dense (˜ 300 g/cm^3) DT fuel wit...

The 2D/3D hybrid plasma simulation code Zuma is used to analyze the advantages of imposing a magnetic field in order to enhance the transport of energetic electrons from the source region to the dense fuel assembly. Results from a variety of target and cone configurations will be presented. Zuma also calculates the Kalpha production detected in exp...

This paper shows work at Lawrence Livermore National Lab (LLNL) devoted to modeling the propagation of, and heating by, a relativistic electron beam in a idealized dense fuel assembly for fast ignition [1]. The implicit particle-in-cell (PIC) code LSP is used. Experiments planned on the National Ignition Facility (NIF) in the next few years using t...

Fast Ignition is an inertial fusion scheme in which fuel is first assembled and then heated to the ignition temperature with an external heating source. In this note we consider cone and shell implosions where the energy supplied by short pulse lasers is transported to the fuel by electrons. We describe possible failure modes for this scheme and ho...

An alternative to inertial fusion with central ignition is "fast ignition", in which one laser compresses the DT fuel adiabatically and a second laser with a short, very intense pulse heats the compressed core with super-thermal electrons1. One approach to fast ignition entails the introduction of the second laser beam via a hollow cone that pierce...

Early experimental and analytical results for short-pulse, high intensity laser–target scenarios have claimed the existence of significant surface currents along the target edge due to hot electron confinement by electromagnetic surface fields. However, more recent fully integrated-explicit and hybrid-implicit particle-in-cell (PIC) simulations hav...

Detailed angle and energy resolved measurements of positrons ejected from the back of a gold target that was irradiated with an intense picosecond duration laser pulse reveal that the positrons are ejected in a collimated relativistic jet. The laser-positron energy conversion efficiency is ∼2×10{-4}. The jets have ∼20 degree angular divergence and...

The characteristics of relativistic electrons generated in short-pulse laser plasma interactions are important for evaluating the success of the fast ignition concept. The important parameters include the spectrum, laser to electron conversion efficiency, and divergence angle of the electrons at the interface. Simulation results using 3-D particle-...

The viability of fast-ignition (FI) inertial confinement fusion hinges on the efficient transfer of laser energy to the compressed fuel via multi-MeV electrons. Preformed plasma due to the laser prepulse strongly influences ultraintense laser plasma interactions and hot electron generation in the hollow cone of an FI target. We induced a prepulse a...

We describe our ongoing work in developing indirect drive Fast Ignition (FI) target designs to be fielded on the National Ignition Facility. Previous efforts [Bull. Am. Phys. Soc. 53, 52 (2008)] focused on capsule designs using deuterium-tritium fuel and doped beryllium ablators. In keeping with the need to diagnose electron beam heating of the ass...

We investigate the hydrodynamic response of plasma gradients during the interaction with ultraintense energetic laser pulses using kinetic particle simulations. Energetic laser pulses are capable of compressing preformed plasma gradients over short times, while accelerating low-density plasma backward. As light is absorbed on a steepened interface,...

Light propagating down a cone and/or impinging on a structured surface in the short-pulse, high intensity laser-matter interaction which generates the hot energetic electrons essential to the fast ignition scheme is studied with particle-in-cell simulations. These more complex geometries lead to both increased laser light absorption and higher temp...

In fast ignition a short-pulse high intensity laser is used to generate relativistic electrons that subsequently deposit their energy into the compressed fuel to initiate a propagating burn wave. A high-density cone is often inserted into the capsule to allow a clear path for the ignition laser to the compressed fuel. The presence of the cone alter...

The fast ignition scheme will involve the generation and transport of a relativistic electron beam, which may be subject to a number of instabilities that act to inhibit energy transport. This study will address the effects of collisions and the initial electron beam distribution on the linear evolution of these instabilities for theoretical distri...

Fast ignition research has reached the stage where point designs are becoming crucial to the identification of key issues and the development of projects to demonstrate high gain fast ignition. The status of point designs for cone coupled electron fast ignition and some of the issues they highlight are discussed.

Proton generation from the interaction of an intense, short pulse laser with a foil target is simulated using the particle-in-cell hybrid code LSP. The efficiencies for proton production are compared for foils having thin coatings of CH, CH ₂ , CH ₄ , and LiH, as well as heavy hydrides such as ErH ₃ . Enhanced effic...

We report the first direct measurements of total absorption of short laser pulses on solid targets in the ultrarelativistic regime. The data show an enhanced absorption at intensities above 10(20) W/cm(2), reaching 60% for near-normal incidence and 80%-90% for 45 degrees incidence. Two-dimensional particle-in-cell simulations demonstrate that such...

We are applying our recently developed, LDRD-funded computational simulation tool to optimize and develop applications of Fast Ignition (FI) for stockpile stewardship. This report summarizes the work performed during a one-year exploratory research LDRD to develop FI point designs for the National Ignition Facility (NIF). These results were suffici...

The Fast Ignition (FI) concept for Inertial Confinement Fusion (ICF) has the potential to provide a significant advance in the technical attractiveness of Inertial Fusion Energy (IFE) reactors. FI differs from conventional 'central hot spot' (CHS) target ignition by using one driver (laser, heavy ion beam or Z-pinch) to create a dense fuel and a se...

In the Fast Ignition (FI) approach to inertial confinement fusion a short-pulse high intensity laser is used to generate relativistic electrons that subsequently deposit their energy into the compressed DT fuel to initiate a propagating burn wave. A gold cone is normally inserted into the cryogenic DT capsule to allow a clear path for the ignition...

The approaching completion of the National Ignition Facility (NIF) in 2010 offers the prospect of large-scale Fast Ignition (FI) experiments in the 2011 time frame. Since NIF will initially be configured in an indirect drive mode, however, capitalizing on this opportunity requires the development of indirect drive FI targets. Previously [Nuc. Fusio...

In this paper, we present hohlraum design and 2-D capsule symmetry calculations for a fast ignitor in Inertial Fusion Energy applications. A hohlraum configuration with low laser incidence angle (between 10 to 20 degree) is designed using the view-factor code GERTIE. Time dependent capsule and wall albedos are obtained from 1-D LASNEX calculations....

Since its acclimation from the ion beam community, the LSP code has been used to model a wide range of laser-plasma configurations relevant to fast ignition research. Given the high density, low temperature regimes of interest for some of these problems, there has been an increased concern for the role collisionality might play in hot electron beam...

In present day scenarios of fast ignition, a short-pulse high intensity laser propagates down a cone to produce hot electrons near the compressed core. Here we report on our continuing study of these cone irradiations in PIC simulations with our code, Z3. Previously we have shown ootnotetextB. F. Lasinski, et al, 9^th International Fast Ignitor Wor...

A crucial issue surrounding the feasibility of fast ignition is the ability to efficiently couple energy from an incident short-pulse laser to a high-density, pre-compressed fuel core. Energy transfer will involve the generation and transport of a relativistic electron beam, which may be subject to a number of instabilities that act to inhibit ener...

FI targets that use laser-generated proton beams for ignition must protect the proton-generating surface from the imploding shell. The protective case surrounding the surface has the potential to change the ion production efficiency and its focus. We have explored these effects in recent experiments on the Titan laser with a focusing surface embedd...

Suprathermal pressure can be a significant parasitic loss in low mass targets illuminated by short-pulse, ultra-high intensity lasers. Recent experiments have used low mass targets as: 1) efficient sources of Kalphagg radiation for radiography applications as well as 2) clean measures of laser to suprathermal electron coupling efficiency because el...

The proton energy distribution generated from the interaction of an intense (Iλ2 ≈ 1020 W/cm2 μm2) short-pulse (100 fs) laser with a thin foil is investigated using energy resolved measurements and 2D collisional PIC-hybrid simulations. The measured absolute proton spectrum is well matched by a 1.7 MeV exponential function for energies <11 MeV. The...

Various gain models have shown the potentially great advantages of fast ignition (FI) inertial confinement fusion (ICF) over its conventional hot spot ignition counterpart (e.g. Atzeni S. 1999 Phys. Plasmas 6 3316; Tabak M. et al 2006 Fusion Sci. Technol. 49 254). These gain models, however, all assume nearly uniform density fuel assemblies. In con...

High‐energy x‐ray backlighters will be valuable for radiography experiments at the National Ignition Facility (NIF), and for radiography of imploded inertial confinement fusion cores using Compton scattering to observe cold, dense plasma. Key considerations are the available backlight brightness, and the backlight size. To quantify these parameters...

There is a need to develop alternate energy sources in the coming century because fossil fuels will become depleted and their use may lead to global climate change. Inertial fusion can become such an energy source, but significant progress must be made before its promise is realized. The high-density approach to inertial fusion suggested by Nuckoll...

Monoenergetic proton radiography was used to make the first measurements of the long-time-scale dynamics and evolution of megagauss laser-plasma-generated magnetic field structures. While a 1-ns 10(14) W/cm2 laser beam is on, the field structure expands in tandem with a hemispherical plasma bubble, maintaining a rigorous 2D cylindrical symmetry. Wi...

The Editorial staff of Nuclear Fusion were shocked by the news of the death of our former Associate Editor for Inertial Confinement (ICF), Bill Hogan. It seems like only yesterday that we saw him at the IAEA Conference in Vilamoura with all his enthusiasm and vigour. During 2005 we kept in electronic contact with him until his successor, Max Tabak,...

Critical issues for the fast ignition of inertial confinement fusion targets, where pre-compressed fuel is ignited by injection of an intense short laser pulse, are (i) the coupling efficiency of the short pulse to the hot electrons that heat the core and (ii) the transverse beam divergence of those electrons inside the dense plasma, i.e., determin...

We present directly and indirectly driven implosion designs for Fast Ignition. Directly driven designs using various laser illumination wavelengths are described. We compare these designs with simple hydrodynamic efficiency models. Capsules illuminated with less than 1 MJ of light with perfect zooming at low intensity and low contrast ratio in powe...

Radiography of the cold dense fuel will be a valuable diagnostic for imploding inertial confinement fusion targets at the National Ignition Facility (NIF). For x-rays with energies between 30 and 200 keV, the main opacity will be Compton scattering. We report on experiments to characterize x-ray emission from low- to high-Z planar foils irradiated...

Isochoric heating of inertially confined fusion plasmas by laser driven MeV electrons or protons is an area of great topical interest in the inertial confinement fusion community, particularly with respect to the fast ignition (FI) proposal to use this technique to initiate burn in a fusion capsule. Experiments designed to investigate electron isoc...

We are developing 15-100 keV high-energy x-ray sources for diagnostic radiography for high energy density experiments on new facilities such as Omega-EP, Z-R and NIF. High-energy x-ray sources can be created from hot electron interactions with target materials when illuminated by high intensity lasers. We have performed experiments to characterize...

Various gain models have shown the potentially great advantages of Fast Ignition (FI) Inertial Confinement Fusion (ICF) over its conventional hotspot ignition counterpart. These gain models, however, all assume nearly uniform-density fuel assemblies. By contrast, typical ICF implosions yield hollowed fuel assemblies with a high-density shell of fue...

The Fast Ignition Program in the United States has enjoyed increased funding in various forms from the Office of Fusion Energy Sciences of the Department of Energy. The program encompasses experiments on large laser facilities at various world-wide locations, and benefits enormously from collaborations with many international scientists. The progra...

Recently, attention has focused on the effects of spherical convergence on the nonlinear phase of Rayleigh-Taylor growth. In particular, for instability growth on spherically converging interfaces, modifications to the predictions of the Layzer model for the secular growth of a single, nonlinear mode have been reported. On the other hand, applicati...

There is a need to develop alternate energy sources in the coming century because fossil fuels will become depleted and their use may lead to global climate change. Inertial fusion can become such an energy source, but significant progress must be made before its promise is realized. The high-density approach to inertial fusion suggested by Nuckoll...

Isochoric heating by electrons has been measured in the two limiting cases of small area thin foils with dominant refluxing and cone-long-wire geometry with negligible refluxing in the wire. Imaging of Cu K alpha fluorescence, crystal x-ray spectroscopy of Cu K shell emission, and XUV imaging at 68eV and 256eV are discussed. Laser power on target w...

With the addition of recent PW shots, the propagation of short-pulse laser generated electron beams have been studied using laser pulse energies from 30 J to 300 J, generating currents up to $\sim $15 MA in solid Al:Cu targets. This is $\sim $5% of the current that will be required in an ignition pulse. To this level, the current appears to simply...

Coupling efficiency, the ratio of the capsule absorbed energy to the driver energy, is a key parameter in ignition target designs. The hohlraum originally proposed for the National Ignition Facility (NIF) [ G. H. Miller, E. I. Moses, and C. R. Wuest, Nucl. Fusion 44, S228 (2004) ] coupled ∼ 11% of the absorbed laser energy to the capsule as x rays....

The characteristics of 22-40 keV K alpha x-ray sources are measured. These high-energy sources are produced by 100 TW and petawatt high-intensity lasers and will be used to develop and implement workable radiography solutions to probe high-Z and dense materials for the high-energy density experiments. The measurements show that the K alpha source s...

The fast ignition (FI) concept requires the generation of a compact, dense, pure fuel mass accessible to an external ignition source. The current baseline FI target is a shell fitted with a re-entrant cone extending to near its center. Conventional direct or indirect drive collapses the shell near the tip of the cone and then an ultra-intense laser...

Fast ignition is an approach to inertial fusion in which precompressed fuel is ignited with an external heat source. This arrangement can, in principle, lead to higher gains than conventional ignition produced by stagnation of convergent flows. In addition, because ignition is separate from the implosion in fast ignition, hydrodynamic mix has less...

Recent attention has focused on the effect of spherical convergence on the nonlinear phase of Rayleigh-Taylor growth. For instability growth on spherically converging interfaces, modifications to the predictions of the Layzer model for the secular growth of a single, nonlinear mode have been reported [D. S. Clark and M. Tabak, Phys. Rev. E 72, 0563...

Highly penetrating proton beams, generated by irradiating a thin foil target with picosecond laser pulses at intensities up to 10^20 Wcm-2 have been used to detect electric and magnetic fields in laser-produced plasmas [1]. More recently experiments to characterize the transient electric and magnetic fields using mono-energetic protons from implodi...

The production of energetic electrons in short-pulse, high-intensity laser-plasma interactions is a key component of the fast ignition concept. In present day scenarios this short-pulse high intensity laser propagates down a cone to produce the hot electrons near the compressed core. PIC simulations with our code, Z3, are used to study the laser pl...

Shock-ignition, a new concept for ICF ignition [C.Zhou, R.Betti Bull APS, v50, 2005], is being studied as a future option for efficiently achieving high gains in large laser facilities such as NIF. Accordingly, this offers the potential for testing: (1)High yield (up to 200MJ), reactor-relevant targets for inertial fusion energy (2)High fusion yiel...

Fast ignited inertially confined fusion targets have potentials for high gain at moderate laser energy. Gain estimates are based on simulations of separate aspects of target evolution and on gain models, and depend critically on ignition requirements and assumptions concerning coupling of the igniting beam to the compressed fuel. In this paper, we...

The Layzer model for the nonlinear evolution of bubbles in the Rayleigh-Taylor instability has recently been generalized to the case of spherically imploding interfaces [D. S. Clark and M. Tabak, Phys. Rev. E 71, 055302(R) (2005)]. The spherical case is more relevant to, e.g., inertial confinement fusion or various astrophysical phenomena when the...

Over the past few years, the emphasis in heavy ion target design has moved from the distributed radiator target to the 'hybrid' target because the hybrid target allows a larger beam focal spot than the distributed radiator (~5?mm radius rather than ~2?mm radius). The larger spot relaxes some of the requirements on the driver, but introduces some ne...

Summary form only given. Laboratory experiments that employ petawatt lasers are rapidly approaching parameter regimes once thought to be the exclusive domain of compact astrophysical objects. In fact, experiments and simulations of petawatt lasers impinging on solid density targets have always shown that some fraction (usually ~10-50%) of laser ene...

We discuss the necessary requirements to create dense electron-positron plasmas in the laboratory and the possibility of using them to investigate certain aspects of various astrophysical phenomena, such as gamma ray burst engines. Earth-based electron-positron plasmas are created during the interaction of ultra-intense laser pulses impinging on a...

One approach for heating a target to "Warm Dense Matter" conditions (similar, for example, to the interiors of giant planets or certain stages in inertial confinement fusion targets), is to use intense ion beams as the heating source (see refs.[6] and [7] and references therein for motivation and accelerator concepts). By consideration of ion beam...

The Heavy Ion Fusion Virtual National Laboratory is developing the intense ion beams needed to drive matter to the High Energy Density regimes required for Inertial Fusion Energy and other applications. An interim goal is a facility for Warm Dense Matter studies, wherein a target is heated volumetrically without being shocked, so that well-defined...