A5002555574- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Laser-Matter Interactions and Applications
- High-pressure geophysics and materials
- Combustion and Detonation Processes
- Energetic Materials and Combustion
- Atomic and Molecular Physics
- Laser Design and Applications
- Nuclear Physics and Applications
- Magnetic confinement fusion research
- Cold Fusion and Nuclear Reactions
- Planetary Science and Exploration
- Astro and Planetary Science
- Fusion materials and technologies
- Gas Dynamics and Kinetic Theory
- Laser Material Processing Techniques
- Ionosphere and magnetosphere dynamics
- Particle Dynamics in Fluid Flows
- Gamma-ray bursts and supernovae
- Nuclear Issues and Defense
- Spacecraft and Cryogenic Technologies
- Ion-surface interactions and analysis
- Astrophysics and Cosmic Phenomena
- Earthquake Detection and Analysis
- Nuclear physics research studies
University of Rochester
2016-2025
Energetics (United States)
2016-2025
Applied Energetics (United States)
2011-2024
Altai State University
2006-2021
Lawrence Livermore National Laboratory
2008-2017
Lipetsk State Technical University
2013
Russian Academy of Sciences
2009
Massachusetts Institute of Technology
2007-2008
Fusion Academy
2008
Fusion (United States)
2008
An analytical model of the nonlinear bubble evolution single-mode, classical Rayleigh-Taylor instability at arbitrary Atwood numbers (A(T)) is presented. The based on an extension Layzer's theory [Astrophys. J. 122, 1 (1955)] previously applied only to fluid-vacuum interfaces (A(T) = 1). provides a continuous from earlier exponential growth regime when velocity saturates U(b) square root [2A(T)/(1+A(T)) (g/C(g)k)], where k perturbation wave number, g interface acceleration, and C(g) 3 for...
A simple procedure is developed to determine the Froude number Fr, effective power index for thermal conduction ν, ablation-front thickness L0, ablation velocity Va, and acceleration g of laser-accelerated fronts. These parameters are determined by fitting density pressure profiles obtained from one-dimensional numerical simulations with analytic isobaric Kull Anisimov [Phys. Fluids 29, 2067 (1986)]. quantities then used calculate growth rate ablative Rayleigh–Taylor instability using theory...
Understanding and designing inertial confinement fusion (ICF) implosions through radiation-hydrodynamics simulations relies on the accurate knowledge of equation state (EOS) deuterium tritium fuels. To minimize drive energy for ignition, imploding shell DT fuel must be kept as cold possible. Such low-adiabat ICF can access to coupled degenerate plasma conditions, in which analytical EOS models become inaccurate due many-body effects. Using path-integral Monte Carlo (PIMC) we have derived a...
Excessive increase in the shell entropy and degradation from spherical symmetry inertial confinement fusion implosions limit compression could impede ignition. The is controlled by accurately timing shock waves launched into at an early stage of implosion. seeding Rayleigh-Taylor instability, main source asymmetry growth, also set times during transit across shell. In this paper we model perturbation growth directly driven targets measured on OMEGA laser system [T. R. Boehly et al., Opt....
Radiative hydrodynamic simulations of implosion experiments on the OMEGA laser system [Boehly et al., Opt. Commun. 133, 495 (1997)] show that energy transfer between crossing beams can reduce absorption by 10%–20%. A new quantitative model for crossed-beam has been developed, allowing one to simulate coupling multiple in expanding corona targets. Scattered-light and bang-time measurements good agreement with predictions this when nonlocal heat transport is employed. The be increased...
Reaching ignition in direct-drive (DD) inertial confinement fusion implosions requires achieving central pressures excess of 100 Gbar. The OMEGA laser system [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] is used to study the physics that are hydrodynamically equivalent designs on National Ignition Facility (NIF) [J. A. Paisner Laser Focus World 30, 75 (1994)]. It shown highest hot-spot (up 40 Gbar) achieved target with a fuel adiabat α ≃ 4, an implosion velocity 3.8 × 107 cm/s, and...
Accurate knowledge about the equation of state (EOS) deuterium is critical to inertial confinement fusion (ICF). Low-adiabat ICF implosions routinely access strongly coupled and degenerate plasma conditions. Using path integral Monte Carlo method, we have derived a first-principles EOS (FPEOS) table deuterium. It first ab initio which completely covers typical implosion trajectory in density temperature ranges ρ=0.002-1596 g/cm3 T=1.35 eV-5.5 keV. Discrepancies internal energy pressure been...
Direct-drive-implosion experiments on the OMEGA laser [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] have showed discrepancies between simulations of scattered (non-absorbed) light levels and measured ones that indicate presence a mechanism reduces coupling efficiency by 10%–20%. This appears to be due crossed-beam energy transfer (CBET) involves electromagnetic-seeded, low-gain stimulated Brillouin scattering. CBET scatters from central portion incoming beam outgoing light, reducing...
Along with laser-indirect (X-ray)-drive and magnetic-drive target concepts, laser direct drive is a viable approach to achieving ignition gain inertial confinement fusion. In the United States, national program has been established demonstrate understand physics of drive. The utilizes Omega Laser Facility conduct implosion coupling at nominally 30-kJ scale laser–plasma interaction MJ National Ignition Facility. This article will discuss motivation challenges for broad-based presently...
A record fuel hot-spot pressure ${P}_{\mathrm{hs}}=56\ifmmode\pm\else\textpm\fi{}7\text{ }\text{ }\mathrm{Gbar}$ was inferred from x-ray and nuclear diagnostics for direct-drive inertial confinement fusion cryogenic, layered deuterium--tritium implosions on the 60-beam, 30-kJ, 351-nm OMEGA Laser System. When hydrodynamically scaled to energy of National Ignition Facility, these achieved a Lawson parameter $\ensuremath{\sim}60%$ value required ignition [A. Bose et al., Phys. Rev. E 94,...
This paper reviews the current direct-drive ignition capsule designed for National Ignition Facility (NIF) [M. D. Campbell and W. J. Hogan, Plasma Phys. Control. Fusion 41, B39 (1999)]. The design consists of a cryogenic deuterium–tritium (DT) shell contained within very thin CH shell. To maintain integrity during implosion, target is placed on an isentrope approximately three times that Fermi-degenerate DT (α=3). One-dimensional studies show robust. Two-dimensional simulations examine...
Theory of the ablative Richtmyer-Meshkov instability is presented. It shown that main stabilizing mechanism ablation-front perturbations during shock transit time dynamic overpressure causes perturbation oscillations. The amplitude oscillation proportional to ${c}_{s}/\sqrt{{V}_{a}{V}_{\mathrm{bl}}}$ and its frequency $\ensuremath{\omega}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}k\sqrt{{V}_{a}{V}_{\mathrm{bl}}}$, where $k$ wave number, ${c}_{s}$, ${V}_{a}$, ${V}_{\mathrm{bl}}$ are...
Hydrodynamic instabilities seeded by laser imprint and surface roughness limit the compression ratio neutron yield in direct-drive inertial confinement fusion target designs. New improved-performance designs use adiabat shaping to increase entropy of only outer portion shell, reducing instability growth. The inner shell is kept on a lower maximize compressibility. implemented using high-intensity picket front main-drive pulse. launches strong shock that decays as it propagates through shell....
The linear stability analysis of accelerated ablation fronts is carried out self-consistently by retaining the effect finite thermal conductivity. Its temperature dependence included through a power law (κ∼Tν) with index ν≳1. growth rate derived for Fr≫1 (Fr Froude number) using boundary layer analysis. self-consistent Atwood number and ablative stabilization term depend on mode wavelength, density gradient scale length, ν. analytic formula shown to be in excellent agreement numerical fit...
Multidimensional hydrodynamic properties of high-adiabat direct-drive plastic-shell implosions on the OMEGA laser system [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] are investigated using multidimensional code, DRACO [D. Keller Bull. Am. Phys. Soc. 44, 37 (1999)]. Multimode simulations including effects nonuniform illumination and target roughness indicate that shell stability during acceleration phase plays a critical role in determining performance. For thick shells remain integral...
Three recent developments in direct-drive target design have enhanced the possibility of achieving high gain on National Ignition Facility (NIF): (1) Laser absorption was increased by almost 50% using wetted-foam targets. (2) Adiabat shaping significantly hydrodynamic stability during acceleration phase implosion without sacrificing gain. (3) Techniques to reduce laser imprint pulse and radiation preheat were developed. These features can be employed for direct-drive-ignition experiments...
The linear stability analysis of accelerated ablation fronts is carried out self-consistently by retaining the effect finite thermal conductivity. Its temperature dependence along with density gradient scale length are adjusted to fit profiles obtained in one-dimensional simulations. effects diffusive radiation transport included through nonlinear conductivity (κ∼Tν). growth rate derived using a boundary layer for Fr≫1 (Fr Froude number) and WKB approximation Fr≪1. self-consistent Atwood...
A model for the deceleration phase and marginal ignition of imploding capsules is derived by solving a set ordinary differential equations describing hot-spot energy balance shell dynamics including return shock propagation. It found that heat flux leaving hot spot goes back in form internal PdV work material ablated off inner-shell surface. Though temperature reduced conduction losses, density increases due to such way pressure approximately independent conduction. For temperatures...
The two-plasmon-decay (TPD) instability in direct-drive irradiation OMEGA [J. M. Soures, R. L. McCrory, C. P. Verdon, et al., Phys. Plasmas 3, 2108 (1996)] experiments is seen the half-integer harmonic emission. Experimental time-resolved ω/2 and 3ω/2 spectra indicate that linear theory for absolute TPD reasonably predicts thresholds. plasma wave do not, however, agree at all with predictions of theory. This most likely a consequence nonlinear evolution this once it above threshold....
The performance of triple-picket deuterium-tritium cryogenic target designs on the OMEGA Laser System [T. R. Boehly, Opt. Commun. 133, 495 (1997)] is reported. These facilitate control shock heating in low-adiabat inertial confinement fusion targets. Areal densities up to 300 mg/cm2 (the highest ever measured implosions) are inferred experiments with an implosion velocity approximately 3x10(7) cm/s driven at peak laser intensities 8x10(14) W/cm2. Extension these ignition National Ignition...
Significant progress in direct-drive inertial confinement fusion (ICF) research has been made since the completion of 60-beam, 30-kJUV OMEGA Laser System [Boehly, Opt. Commun. 133, 495 (1997)] 1995. A theory ignition requirements, applicable to any ICF concept, developed. Detailed understanding laser-plasma coupling, electron thermal transport, and hot-electron preheating lead measurement neutron-averaged areal densities ∼200mg∕cm2 cryogenic target implosions. These correspond an estimated...