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22 results on '"Nathan Meezan"'

1. Neutron Time-of-Flight Measurements of Charged-Particle Energy Loss in Inertial Confinement Fusion Plasmas

Author

M. Gatu Johnson, A. J. Mackinnon, Frank Graziani, Wolfgang Stoeffl, S. Le Pape, Nathan Meezan, Laurent Divol, D. H. Schneider, D. A. Shaughnessy, James McNaney, L. F. Berzak Hopkins, Gary Grim, E. P. Hartouni, Mark Eckart, Robert Hatarik, Shahab Khan, S. P. Hatchett, C. B. Yeamans, A. K. Hayes, H. G. Rinderknecht, J. P. Knauer, Stephanie Hansen, Dirk O. Gericke, Daniel Sayre, J. A. Caggiano, Alex Zylstra, C. J. Cerjan, and S. M. Sepke

Subjects
Physics, Thermonuclear fusion, General Physics and Astronomy, Magnetic confinement fusion, Implosion, Fusion power, 01 natural sciences, Charged particle, Nuclear physics, 0103 physical sciences, Neutron, 010306 general physics, National Ignition Facility, Inertial confinement fusion, QC
Abstract

Neutron spectra from secondary ^{3}H(d,n)α reactions produced by an implosion of a deuterium-gas capsule at the National Ignition Facility have been measured with order-of-magnitude improvements in statistics and resolution over past experiments. These new data and their sensitivity to the energy loss of fast tritons emitted from thermal ^{2}H(d,p)^{3}H reactions enable the first statistically significant investigation of charged-particle stopping via the emitted neutron spectrum. Radiation-hydrodynamic simulations, constrained to match a number of observables from the implosion, were used to predict the neutron spectra while employing two different energy loss models. This analysis represents the first test of stopping models under inertial confinement fusion conditions, covering plasma temperatures of k_{B}T≈1-4 keV and particle densities of n≈(12-2)×10^{24} cm^{-3}. Under these conditions, we find significant deviations of our data from a theory employing classical collisions whereas the theory including quantum diffraction agrees with our data.

Published
2019
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2. Developing an Experimental Basis for Understanding Transport in NIF Hohlraum Plasmas

Author

Jeremy Kroll, J. D. Kilkenny, Robert L. Kauffman, G. Pérez-Callejo, William Farmer, Marilyn Schneider, D. B. Thorn, Duane A. Liedahl, H. Chen, Mark Sherlock, Otto Landen, O. S. Jones, J. Jaquez, Steve MacLaren, L. J. Suter, Klaus Widmann, A. Nikroo, J. D. Moody, M. A. Barrios, and Nathan Meezan

Subjects
Physics, General Physics and Astronomy, Plasma, Kinetic energy, Laser, 01 natural sciences, 010305 fluids & plasmas, law.invention, Computational physics, Magnetic field, Ignition system, law, Hohlraum, 0103 physical sciences, Electron temperature, 010306 general physics, National Ignition Facility
Abstract

We report on the first multilocation electron temperature (T_{e}) and flow measurements in an ignition hohlraum at the National Ignition Facility using the novel technique of mid-Z spectroscopic tracer "dots." The measurements define a low resolution "map" of hohlraum plasma conditions and provide a basis for the first multilocation tests of particle and energy transport physics in a laser-driven x-ray cavity. The data set is consistent with classical heat flow near the capsule but reduced heat flow near the laser entrance hole. We evaluate the role of kinetic effects, self-generated magnetic fields, and instabilities in causing spatially dependent heat transport in the hohlraum.

Published
2018
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3. Fusion Energy Output Greater than the Kinetic Energy of an Imploding Shell at the National Ignition Facility

Author

S. R. Nagel, L. F. Berzak Hopkins, D. A. Callahan, E. L. Dewald, Petr Volegov, T. Ma, Suhas Bhandarkar, D. H. Edgell, S. Le Pape, Pierre Michel, Nobuhiko Izumi, Jose Milovich, P. K. Patel, B. J. MacGowan, Darwin Ho, C. B. Yeamans, M. Havre, Laurent Divol, David N. Fittinghoff, Maria Gatu-Johnson, Shahab Khan, Joseph Ralph, Nathan Meezan, C. Wild, G. A. Kyrala, A. Nikroo, Michael Stadermann, J. Crippen, Jason Ross, A. J. Mackinnon, S. W. Haan, Omar Hurricane, David Strozzi, L. R. Bennedetti, Clement Goyon, Robert Hatarik, T. Bunn, J. Jaquez, Andrew MacPhee, Jürgen Biener, Marius Millot, Neal Rice, C. R. Weber, Daniel Casey, and Art Pak

Subjects
Materials science, General Physics and Astronomy, chemistry.chemical_element, Fusion power, Kinetic energy, 01 natural sciences, 010305 fluids & plasmas, chemistry, Hohlraum, 0103 physical sciences, Radiative transfer, Area density, Atomic physics, 010306 general physics, National Ignition Facility, Stagnation pressure, Helium
Abstract

A series of cryogenic, layered deuterium-tritium (DT) implosions have produced, for the first time, fusion energy output twice the peak kinetic energy of the imploding shell. These experiments at the National Ignition Facility utilized high density carbon ablators with a three-shock laser pulse (1.5 MJ in 7.5 ns) to irradiate low gas-filled (0.3 mg/cc of helium) bare depleted uranium hohlraums, resulting in a peak hohlraum radiative temperature ∼290 eV. The imploding shell, composed of the nonablated high density carbon and the DT cryogenic layer, is, thus, driven to velocity on the order of 380 km/s resulting in a peak kinetic energy of ∼21 kJ, which once stagnated produced a total DT neutron yield of 1.9×10^{16} (shot N170827) corresponding to an output fusion energy of 54 kJ. Time dependent low mode asymmetries that limited further progress of implosions have now been controlled, leading to an increased compression of the hot spot. It resulted in hot spot areal density (ρr∼0.3 g/cm^{2}) and stagnation pressure (∼360 Gbar) never before achieved in a laboratory experiment.

Published
2018

4. First Liquid Layer Inertial Confinement Fusion Implosions at the National Ignition Facility

Author

Nathan Meezan, T. Braun, B. J. Kozioziemski, A. V. Hamza, L. F. Berzak Hopkins, Paul A. Bradley, Monika M. Biener, R. J. Leeper, C. Kong, A. Nikroo, George A. Kyrala, Doug Wilson, C. F. Walters, S. A. Yi, Hans W. Herrmann, Robert R. Peterson, Steven H. Batha, R. C. Shah, J. Biener, R. E. Olson, J. D. Sater, Lin Yin, J. W. Crippen, John Kline, Brian Haines, and Alex Zylstra

Subjects
Materials science, Nuclear engineering, General Physics and Astronomy, Sense (electronics), Nova (laser), Radiation, 01 natural sciences, 010305 fluids & plasmas, law.invention, Ignition system, Deuterium, law, 0103 physical sciences, Neutron, 010306 general physics, National Ignition Facility, Inertial confinement fusion
Abstract

The first cryogenic deuterium and deuterium-tritium liquid layer implosions at the National Ignition Facility (NIF) demonstrate D_{2} and DT layer inertial confinement fusion (ICF) implosions that can access a low-to-moderate hot-spot convergence ratio (12CR25). Previous ICF experiments at the NIF utilized high convergence (CR30) DT ice layer implosions. Although high CR is desirable in an idealized 1D sense, it amplifies the deleterious effects of asymmetries. To date, these asymmetries prevented the achievement of ignition at the NIF and are the major cause of simulation-experiment disagreement. In the initial liquid layer experiments, high neutron yields were achieved with CRs of 12-17, and the hot-spot formation is well understood, demonstrated by a good agreement between the experimental data and the radiation hydrodynamic simulations. These initial experiments open a new NIF experimental capability that provides an opportunity to explore the relationship between hot-spot convergence ratio and the robustness of hot-spot formation during ICF implosions.

Published
2016

5. Generation and Beaming of Early Hot Electrons onto the Capsule in Laser-Driven Ignition Hohlraums

Author

Harry Robey, Nathan Meezan, E. L. Dewald, Pierre Michel, Debra Callahan, Laurent Divol, Omar Hurricane, M. J. Edwards, Tilo Döppner, A. J. Mackinnon, Matthias Hohenberger, Benjamin Bachmann, Jose Milovich, Frederic V. Hartemann, Otto Landen, Felicie Albert, and Arthur Pak

Subjects
Physics, business.industry, Waves in plasmas, Bremsstrahlung, General Physics and Astronomy, Electron, Plasma, Laser, 01 natural sciences, 010305 fluids & plasmas, law.invention, Optics, Physics::Plasma Physics, law, Hohlraum, 0103 physical sciences, 010306 general physics, business, National Ignition Facility, Inertial confinement fusion
Abstract

In hohlraums for inertial confinement fusion (ICF) implosions on the National Ignition Facility, suprathermal hot electrons, generated by laser plasma instabilities early in the laser pulse ("picket") while blowing down the laser entrance hole (LEH) windows, can preheat the capsule fuel. Hard x-ray imaging of a Bi capsule surrogate and of the hohlraum emissions, in conjunction with the measurement of time-resolved bremsstrahlung spectra, allows us to uncover for the first time the directionality of these hot electrons and infer the capsule preheat. Data and Monte Carlo calculations indicate that for most experiments the hot electrons are emitted nearly isotropically from the LEH. However, we have found cases where a significant fraction of the generated electrons are emitted in a collimated beam directly towards the capsule poles, where their local energy deposition is up to 10× higher than the average preheat value and acceptable levels for ICF implosions. The observed "beaming" is consistent with a recently unveiled multibeam stimulated Raman scattering model [P. Michel et al., Phys. Rev. Lett. 115, 055003 (2015)], where laser beams in a cone drive a common plasma wave on axis. Finally, we demonstrate that we can control the amount of generated hot electrons by changing the laser pulse shape and hohlraum plasma.

Published
2015

6. First High-Convergence Cryogenic Implosion in a Near-Vacuum Hohlraum

Author

J. D. Moody, Michael Stadermann, Andrew MacPhee, George A. Kyrala, E. Woerner, J. A. Church, D. A. Callahan, Gary Grim, Daniel Sayre, Abbas Nikroo, T. Ma, Wolfgang Stoeffl, Laurent Divol, James Ross, L. F. Berzak Hopkins, D. Hoover, Mark Eckart, Laura Robin Benedetti, Robert Hatarik, M. Gatu Johnson, Richard Town, A. J. Mackinnon, Shahab Khan, Hans W. Herrmann, Frank E. Merrill, S. M. Sepke, J. A. Caggiano, Jeremy Kroll, Harry Robey, James McNaney, Rebecca Dylla-Spears, C. B. Yeamans, A. V. Hamza, H. Huang, E. P. Hartouni, Matthias Hohenberger, David C. Clark, J. D. Kilkenny, Carl Wilde, D. H. Edgell, Darwin Ho, P. K. Patel, M. J. Edwards, Tilo Döppner, Art Pak, Nobuhiko Izumi, Denise Hinkel, Cliff Thomas, Jose Milovich, R. M. Bionta, Joseph Ralph, Otto Landen, B. E. Yoxall, Michael Schneider, Nathan Meezan, J. Sater, S. Le Pape, Petr Volegov, N. Guler, C. J. Cerjan, David N. Fittinghoff, C. Wild, D. K. Bradley, B. J. Kozioziemski, J. E. Field, O. S. Jones, E. J. Bond, Juergen Biener, S. W. Haan, W. W. Hsing, and J. R. Rygg

Subjects
Physics, business.industry, General Physics and Astronomy, Implosion, Plasma, Laser, Symmetry (physics), Pulse (physics), law.invention, Nuclear physics, Optics, Physics::Plasma Physics, Hohlraum, law, Neutron, National Ignition Facility, business
Abstract

Recent experiments on the National Ignition Facility [M. J. Edwards et al., Phys. Plasmas 20, 070501 (2013)] demonstrate that utilizing a near-vacuum hohlraum (low pressure gas-filled) is a viable option for high convergence cryogenic deuterium-tritium (DT) layered capsule implosions. This is made possible by using a dense ablator (high-density carbon), which shortens the drive duration needed to achieve high convergence: a measured 40% higher hohlraum efficiency than typical gas-filled hohlraums, which requires less laser energy going into the hohlraum, and an observed better symmetry control than anticipated by standard hydrodynamics simulations. The first series of near-vacuum hohlraum experiments culminated in a 6.8 ns, 1.2 MJ laser pulse driving a 2-shock, high adiabat (α ~ 3.5) cryogenic DT layered high density carbon capsule. This resulted in one of the best performances so far on the NIF relative to laser energy, with a measured primary neutron yield of 1.8 X 10¹⁵ neutrons, with 20% calculated alpha heating at convergence ~27X.

Published
2015
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7. Thin Shell, High Velocity Inertial Confinement Fusion Implosions on the National Ignition Facility

Author

T. G. Parham, J. Sater, S. Le Pape, George A. Kyrala, D. A. Callahan, Jay D. Salmonson, T. Ma, David N. Fittinghoff, Nobuhiko Izumi, D. K. Bradley, Joseph Ralph, R. M. Bionta, Otto Landen, O. S. Jones, Peter M. Celliers, Hans W. Herrmann, M. D. Rosen, E. L. Dewald, Robert Hatarik, S. N. Dixit, B. J. MacGowan, E. J. Bond, Gary Grim, Abbas Nikroo, M. A. Barrios, Rebecca Dylla-Spears, J. P. Knauer, Andrew MacPhee, B. J. Kozioziemski, Daniel Sayre, J. E. Field, J. A. Church, D. Shaughnessy, D. H. Edgell, Denise Hinkel, Nathan Meezan, Laura Robin Benedetti, P. K. Patel, Richard Town, P. T. Springer, T. Kohut, Shahab Khan, W. W. Hsing, Daniel Casey, J. D. Kilkenny, Harry Robey, Alan S. Wan, J. D. Moody, C. B. Yeamans, C. J. Cerjan, J. A. Caggiano, M. Gatu Johnson, Carl Wilde, Bruce Remington, Andrea Kritcher, A. J. Mackinnon, M. J. Edwards, Tilo Döppner, Art Pak, Frank E. Merrill, J. R. Rygg, Marilyn Schneider, Klaus Widmann, T. R. Dittrich, Petr Volegov, L. F. Berzak Hopkins, S. W. Haan, R. Tommasini, Johan Frenje, H.-S. Park, Omar Hurricane, S. R. Nagel, Brian Spears, and N. Guler

Subjects
Physics, business.industry, General Physics and Astronomy, Feedthrough, Hot spot (veterinary medicine), Laser, Instability, law.invention, Ignition system, Nominal size, Optics, law, National Ignition Facility, business, Inertial confinement fusion
Abstract

Experiments have recently been conducted at the National Ignition Facility utilizing inertial confinement fusion capsule ablators that are 175 and 165 μm in thickness, 10% and 15% thinner, respectively, than the nominal thickness capsule used throughout the high foot and most of the National Ignition Campaign. These three-shock, high-adiabat, high-foot implosions have demonstrated good performance, with higher velocity and better symmetry control at lower laser powers and energies than their nominal thickness ablator counterparts. Little to no hydrodynamic mix into the DT hot spot has been observed despite the higher velocities and reduced depth for possible instability feedthrough. Early results have shown good repeatability, with up to 1/2 the neutron yield coming from α-particle self-heating.

Published
2015
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8. Observation of a Reflected Shock in an Indirectly Driven Spherical Implosion at the National Ignition Facility

Author

L. F. Berzak Hopkins, A. J. Mackinnon, Laurent Divol, Hans W. Herrmann, Klaus Widmann, Michael Rosenberg, Alex Zylstra, Hans Rinderknecht, Nathan Meezan, R. D. Petrasso, S. Le Pape, Maria Gatu-Johnson, J. D. Kilkenny, Johan Frenje, Tammy Ma, G. Grimm, James McNaney, Daniel Casey, J. P. Knauer, and Arthur Pak

Subjects
Physics, Opacity, Astrophysics::High Energy Astrophysical Phenomena, General Physics and Astronomy, Implosion, Radius, Thermal conduction, Computational physics, Shock (mechanics), Heat flux, Physics::Plasma Physics, Hohlraum, Atomic physics, National Ignition Facility
Abstract

A 200 μm radius hot spot at more than 2 keV temperature, 1 g/cm^{3} density has been achieved on the National Ignition Facility using a near vacuum hohlraum. The implosion exhibits ideal one-dimensional behavior and 99% laser-to-hohlraum coupling. The low opacity of the remaining shell at bang time allows for a measurement of the x-ray emission of the reflected central shock in a deuterium plasma. Comparison with 1D hydrodynamic simulations puts constraints on electron-ion collisions and heat conduction. Results are consistent with classical (Spitzer-Harm) heat flux.

Published
2014
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9. Novel characterization of capsule x-ray drive at the National Ignition Facility

Author

Denise Hinkel, J. H. Hammer, Nathan Meezan, Joseph Ralph, B. E. Yoxall, John Moody, Steve MacLaren, M. L. Kervin, Perry M. Bell, Klaus Widmann, T. M. Guymer, D. K. Bradley, Alastair Moore, M. J. Edwards, Laura Robin Benedetti, W. W. Hsing, and Marilyn Schneider

Subjects
Physics, Ignition system, law, Hohlraum, Nuclear engineering, X-ray, General Physics and Astronomy, Implosion, National Ignition Facility, law.invention, Characterization (materials science), Direct measure
Abstract

Indirect drive experiments at the National Ignition Facility are designed to achieve fusion by imploding a fuel capsule with x rays from a laser-driven hohlraum. Previous experiments have been unable to determine whether a deficit in measured ablator implosion velocity relative to simulations is due to inadequate models of the hohlraum or ablator physics. ViewFactor experiments allow for the first time a direct measure of the x-ray drive from the capsule point of view. The experiments show a 15%--25% deficit relative to simulations and thus explain nearly all of the disagreement with the velocity data. In addition, the data from this open geometry provide much greater constraints on a predictive model of laser-driven hohlraum performance than the nominal ignition target.

Published
2013

10. Onset of Hydrodynamic Mix in High-Velocity, Highly Compressed Inertial Confinement Fusion Implosions

Author

S. Le Pape, Damien Hicks, V. A. Smalyuk, J. D. Moody, E. L. Dewald, D. A. Callahan, T. Ma, M. H. Key, Joseph Ralph, G. A. Kyrala, Daniel Clark, Harry Robey, Otto Landen, Edward I. Moses, Brian Spears, Jason Ross, B. A. Hammel, D. K. Bradley, Nobuhiko Izumi, S. V. Weber, Siegfried Glenzer, Laura Robin Benedetti, Richard Town, Shahab Khan, P. T. Springer, A. J. Mackinnon, Sean Regan, S. N. Dixit, L. J. Suter, O. S. Jones, T. G. Parham, Bruce Remington, H.-S. Park, Tilo Döppner, Art Pak, Gary Grim, R. Tommasini, L. J. Atherton, J. D. Kilkenny, W. W. Hsing, S. W. Haan, P. M. Celliers, Melissa Edwards, S. M. Glenn, P. K. Patel, D. H. Edgell, Andrew MacPhee, Nathan Meezan, John Kline, C. J. Cerjan, J. D. Lindl, Reuben Epstein, and B. J. MacGowan

Subjects
Materials science, General Physics and Astronomy, Implosion, Magnetic confinement fusion, Hot spot (veterinary medicine), Laser, law.invention, Nuclear physics, Hohlraum, law, Atomic physics, National Ignition Facility, Inertial confinement fusion, Energy (signal processing)
Abstract

Deuterium-tritium inertial confinement fusion implosion experiments on the National Ignition Facility have demonstrated yields ranging from 0.8 to $7\ifmmode\times\else\texttimes\fi{}{10}^{14}$, and record fuel areal densities of 0.7 to $1.3\text{ }\text{ }\mathrm{g}/{\mathrm{cm}}^{2}$. These implosions use hohlraums irradiated with shaped laser pulses of 1.5--1.9 MJ energy. The laser peak power and duration at peak power were varied, as were the capsule ablator dopant concentrations and shell thicknesses. We quantify the level of hydrodynamic instability mix of the ablator into the hot spot from the measured elevated absolute x-ray emission of the hot spot. We observe that DT neutron yield and ion temperature decrease abruptly as the hot spot mix mass increases above several hundred ng. The comparison with radiation-hydrodynamic modeling indicates that low mode asymmetries and increased ablator surface perturbations may be responsible for the current performance.

Published
2013
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11. Hot-Spot Mix in Ignition-Scale Inertial Confinement Fusion Targets

Author

V. A. Smalyuk, Richard Town, O. S. Jones, Roberto Mancini, S. H. Glenzer, Nathan Meezan, J. D. Kilkenny, Joseph J. MacFarlane, A. V. Hamza, P. T. Springer, Howard A. Scott, Sean Regan, S. N. Dixit, T. Ma, Melissa Edwards, A. Nikroo, David R. Farley, Joseph Ralph, Otto Landen, R. L. McCrory, S. M. Glenn, T. C. Sangster, K. B. Fournier, Tilo Döppner, G. A. Kyrala, S. W. Haan, Damien Hicks, D. D. Meyerhofer, Debra Callahan, D. K. Bradley, Gilbert Collins, Nobuhiko Izumi, Igor Golovkin, John Kline, H.-S. Park, A. J. Mackinnon, Reuben Epstein, Bruce Remington, B. A. Hammel, M. A. Barrios, L. J. Suter, and C. J. Cerjan

Subjects
Materials science, Quantitative Biology::Neurons and Cognition, Doping, Mixing (process engineering), General Physics and Astronomy, Hot spot (veterinary medicine), law.invention, Ignition system, Physics::Plasma Physics, law, Neutron, Atomic physics, National Ignition Facility, Spectroscopy, Inertial confinement fusion
Abstract

Mixing of plastic ablator material, doped with Cu and Ge dopants, deep into the hot spot of ignition-scale inertial confinement fusion implosions by hydrodynamic instabilities is diagnosed with x-ray spectroscopy on the National Ignition Facility. The amount of hot-spot mix mass is determined from the absolute brightness of the emergent Cu and Ge K-shell emission. The Cu and Ge dopants placed at different radial locations in the plastic ablator show the ablation-front hydrodynamic instability is primarily responsible for hot-spot mix. As a result, low neutron yields and hot-spot mix mass between 34(–13,+50) ng and 4000(–2970,+17 160) ng are observed.

Published
2013
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12. Assembly of High-Areal-Density Deuterium-Tritium Fuel from Indirectly Driven Cryogenic Implosions

Author

E. Giraldez, K. N. La Fortune, Mark W. Bowers, David R. Farley, Steve Glenn, W. H. Courdin, C. A. Thomas, P. S. Datte, K. M. Knittel, B. Haid, C. Stoeckl, K. Moreno, James Knauer, Edward I. Moses, S. W. Haan, N. Guler, J. J. Klingman, P. M. Celliers, P. T. Springer, B. J. Kozioziemski, H. F. Robey, J. D. Sater, A. J. MacKinnon, S. Weaver, N. E. Palmer, R. Bionta, M. A. Barrios, S. G. Brass, L. V. Berzins, Gordon A. Chandler, G. Frieders, Chris Haynam, E. P. Hartouni, Gary Wayne Cooper, G. N. McHalle, Marilyn Schneider, Chimpén Ruiz, Abbas Nikroo, R. J. Fortner, Hans Rinderknecht, Joseph Ralph, N. Simanovskaia, Michael J. Moran, S. J. Cohen, Pierre Michel, R. J. Leeper, Ogden Jones, G. LaCaille, T. G. Parham, R. Benedetti, R. P. J. Town, Eduard Dewald, P. Di Nicola, D. H. Munro, S. C. Burkhart, L. J. Atherton, Maria Gatu Johnson, R. W. Patterson, Hans W. Herrmann, A. Zylestra, Mahalia Jackson, John Lindl, David K. Bradley, Steven Weber, E. S. Palma, James McNaney, John Kline, M. J. Shaw, S. N. Dixit, T. A. Land, Daniel Casey, Gilbert Collins, P. W. McKenty, Paul J. Wegner, Brian Spears, C. Marshall, K. Widmann, D. G. Mathisen, Vladimir Glebov, R. E. Olson, Alex V. Hamza, R. F. Burr, Frank E. Merrill, Owen B. Drury, M. Hermann, Sean Regan, Rebecca Dylla-Spears, C. Clay Widmayer, Nathan Meezan, J. R. Kimbrough, G. Heestand, R. K. Kirkwood, Daniel Clark, R. Saunders, B.M. VanWonterghem, R. Lowe-Webb, K.S. Jancaitis, Perry M. Bell, Pamela K. Whitman, J. A. Caggiano, Damien Hicks, Charles Cerjan, R. J. Wallace, B. K. Young, P. A. Arnold, R. Tommasini, Robert L. Kauffman, A. G. Nelson, E. J. Bond, Alastair Moore, J. R. Cox, Steven H. Batha, Siegfried Glenzer, Bruce Hammel, J Eggert, B. Felker, Laurent Divol, D. A. Callahan, R. B. Ehrlich, Andrew MacPhee, Johan Frenje, D. H. Schneider, Evan Mapoles, Charles D. Orth, R. Prasad, Jose Milovich, K. G. Krauter, G. Gururangan, R. D. Wood, R. C. Ashabranner, E. G. Dzenitis, G. W. Krauter, John M. Dzenitis, J. P. Holder, Prav Patel, B. J. MacGowan, D. N. Fittinghoff, L. J. Lagin, Nobuhiko Izumi, J. M. Dinicola, D. L. Blueuel, Stephan Friedrich, G. Ross, D. H. Edgell, C. F. Walters, James E. Fair, J. D. Kilkenny, Craig Sangster, John Moody, Mary Sue Richardson, R. A. Zacharias, Robert Hatarik, D. Latray, David C. Eder, O. L. Landen, M. J. Eckart, T. Kohut, R. D. Petrasso, J. D. Salmonsen, G. A. Kyrala, Gary Grim, K. D. Hahn, Steve Hatchett, T. Ma, Suhas Bhandarkar, Wolfgang Stoeffl, G Brunton, L. J. Suter, Thomas Boehly, L. A. Bernstein, M. J. Edwards, Tilo Döppner, David Larson, S. Lepape, Dan Kalantar, G. Erbert, and Doug Wilson

Subjects
Ignition system, Materials science, Deuterium, Hohlraum, law, Nuclear engineering, General Physics and Astronomy, Implosion, Neutron, Area density, Radius, National Ignition Facility, law.invention
Abstract

The National Ignition Facility has been used to compress deuterium-tritium to an average areal density of ~1.0±0.1 g cm(-2), which is 67% of the ignition requirement. These conditions were obtained using 192 laser beams with total energy of 1-1.6 MJ and peak power up to 420 TW to create a hohlraum drive with a shaped power profile, peaking at a soft x-ray radiation temperature of 275-300 eV. This pulse delivered a series of shocks that compressed a capsule containing cryogenic deuterium-tritium to a radius of 25-35 μm. Neutron images of the implosion were used to estimate a fuel density of 500-800 g cm(-3).

Published
2012
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13. Publisher’s Note: Demonstration of Ignition Radiation Temperatures in Indirect-Drive Inertial Confinement Fusion Hohlraums [Phys. Rev. Lett.106, 085004 (2011)]

Author

B. L. Pepmeier, D. L. Hodtwalker, B. V. Beeman, J. D. Hollis, P. S. Yang, S. A. Silva, M. J. Richardson, J. L. Vaher, K. Gu, B. N. M. Balaoing, J. E. Krammen, P. J. van Arsdall, N. I. Spafford, M. M. Montoya, M. A. Jackson, F. W. Chambers, J. Grippen, M. Neto, P. H. Gschweng, J. D. Moody, C. A. Haynam, S. Huber, A. P. Ludwigsen, E T Alger, G. M. Curnow, J. Watkins, J. C. Ellefson, S. Sailors, B. McHale, L. F. Alvarez, H. Chandrasekaran, T. E. Mills, Cliff Thomas, P. L. Stratton, R. Zacharias, J. D. Hitchcock, P. M. Bell, J. F. Meeker, E. L. Dewald, R. K. Butlin, T. G. Stone, K. P. Youngblood, Mark W. Bowers, M. Runkel, E. Padilla, M. W. Owens, S. S. Alvarez, J. G. Soto, L. J. Atherton, J. McBride, W. A. Reid, M. Y. Mauvais, G. Heestand, O. D. Edwards, S. W. Lane, A. A. Marsh, T. N. Malsbury, S. R. Robison, P. M. Danforth, J. D. Kilkenny, J. A. Baltz, M. J. Dailey, R. C. Montesanti, J. D. Driscoll, B. J. MacGowan, M. K. Shiflett, Donald F. Browning, F. J. Lopez, C. R. Gibson, F. E. Wade, R. Darbee, Mark R. Hermann, B Fishler, Y. Chen, Edward I. Moses, G. A. Kyrala, R. D. Demaret, J. G. Lown, M. D. Magat, S. Azevedo, G. Erbert, R. K. Kirkwood, K. Charron, Harry B. Radousky, R. T. Shelton, M. E. Sheldrick, R. R. Lyons, C. T. Warren, Paul J. Wegner, P. V. Amick, B. Johnson, G. Hermes, K. M. Morriston, G. A. Keating, T. G. Parham, K. S. Andersson, G. Ross, C. H. Ellerbee, D. A. Callahan, A. S. Rivenes, C. B. Foxworthy, M. C. Johnson, R. Miramontes-Ortiz, P. T. Springer, P. Datte, T. Kohut, J. Neumann, A. J. van Prooyen, C. Thai, M. J. Edwards, K. Work, Tilo Döppner, K. D. Pletcher, G. Frieder, D. S. Hey, T. Ma, A. J. Churby, I. L. Maslennikov, M. C. Witte, Siegfried Glenzer, G. J. Mauger, B. E. Smith, Suhas Bhandarkar, S. C. Burkhart, Joseph Ralph, T. J. Clancy, E. Ng, Thomas J. Johnson, K. L. Griffin, Rolf K. Reed, J. Braucht, R. Rinnert, J.M.Fisher, J. M. Di Nicola, N. Lao, A. L. Throop, S. Hunter, R. L. Rampke, Nathan Meezan, D. A. Barker, Otto Landen, Mark Eckart, M. A. Bergonia, K. N. La Fortune, J. R. Kimbrough, T. R. Huppler, R. A. London, G. L. Tietbohl, J. J. Rhodes, Christoph Niemann, Richard Town, W. J. Fabyan, Joseph W. Carlson, K. M. Skulina, G. Pavel, T. W. Phillips, B. D. Cline, R. G. Hartley, R. J. Wallace, T. L. Lee, C. C. Widmayer, Steven H. Langer, L. F. Finnie, J. Morris, G. T. Villanueva, S. W. Kramer, L. K. Smith, J. W. Florio, D. Pigg, J. L. Vickers, A. S. Runtal, F. E. Coffield, D. G. Cocherell, Pamela K. Whitman, S. Le Pape, Michael Stadermann, E. A. Stout, J. Liebman, V. K. Lakamsani, D. K. Bradley, J. A. Borgman, D. G. Mathisen, M. D. Vergino, P. A. Arnold, Kenneth S. Jancaitis, M. D. Rosen, Jeremy Kroll, J. Dugorepec, M. F. Swisher, J. M. Tillman, D. Pendleton, D. E. Speck, E. Mertens, K. King, Q. M. Ngo, G. Bardsley, E. A. Tekle, R. Costa, Robert L. Kauffman, D. T. Boyle, J. E. Hamblen, D. M. Lord, B. L. Lechleiter, M.S.Hutton, T. Fung, J. R. Schaffer, E. M. Giraldez, S. N. Dixit, John R. Celeste, Laurent Divol, L. C. Clowdus, B. K. Young, D. Trummer, H. Gonzales, B. P. Golick, D. T. Maloy, J. P. Holder, Wendi Sweet, S. R. Marshall, G. J. Edwards, Sally Andrews, G. A. Deis, L. J. Bernardez, D. Larson, L. L. Silva, A. McGrew, G Brunton, S. M. Glenn, Alexander Thomas, Jay D. Salmonson, R. E. Olson, C. M. Estes, Wade H. Williams, K. G. Koka, A. I. Barnes, M. A. Vitalich, A. Y. Chakicherla, J. L. Reynolds, B. Haid, J. T. Salmon, L. V. Berzins, O. S. Jones, B. A. Wilson, M. G. Miller, L. M. Kegelmeyer, Mark J. Schmitt, E. J. Bond, D. R. Bopp, G. T. Lau, N. W. Lum, Kevin S. White, J. T. Fink, D. R. Hart, Marilyn Schneider, F. Stanley, D. B. Dobson, F. Barbosa, L. J. Suter, M. Shor, A. V. Hamza, D. L. Hardy, T. McCarville, D. L. Hipple, C. J. Roberts, P. W. Edwards, R. W. Patterson, Ronald B. Robinson, J. B. Tassano, B. S. Raimondi, S. R. Hahn, G. Gururangan, P. C. Dupuy, R. L. Hibbard, J. R. Nelson, D. A. Smauley, M. J. Fischer, J. H. Kamperschroer, G. Holtmeier, Andrew MacPhee, E. A. Williams, P. A. Adams, K. G. Krauter, Jose Milovich, Stephen P. Vernon, L. J. Lagin, G. N. Gawinski, J. S. Taylor, G. Antonini, M. P. Johnston, M. C. Valadez, M. A. Weingart, S. L. Edson, John Kline, S. M. Gross, A. Baron, J. D. Tappero, N. L. Orsi, J. A. Davis, J. Klingmann, N. J. Cahayag, Carlos E. Castro, J. D. Lindl, A. T. Rivera, L. R. Belk, S. L. Kenitzer, J. Duncan, K. E. Burns, A. L. Solomon, R. C. Bettenhausen, B. M. Van Wonterghem, S. P. Rogers, R G Beeler, D. Latray, H. K. Loey, T. M. Pannell, B. Felker, T. Frazier, V. Rekow, P. G. Zapata, A. J. Mackinnon, R. W. Carey, P. S. Cardinale, J. Jackson, John Moody, S. Burns, L. Willis, J. L. Bragg, D. E. Petersen, E. G. Dzenitis, D. R. Jedlovec, J. R. Cox, D. E. Hinkel, J. A. Robinson, John R. Bower, E. O. Vergel de Dios, B. A. Hammel, L. M. Burrows, Daniel H. Kalantar, Klaus Widmann, M. J. Christensen, R. Prasad, A. L. Warrick, K. Wilhelmsen, R. Chapman, O. R. Rodriguez, A. W. Huey, B. L. Olejniczak, G. W. Krauter, S. W. Haan, Claire Bishop, H. Zhang, J. B. Alfonso, J. H. Truong, S. Weaver, K. S. Segraves, S. Sommer, J. C. Bell, Y. Lee, S. Shiromizu, R. Saunders, R. N. Fallejo, K. Piston, J. Wen, R. M. Marquez, K. L. Tribbey, S. A. Gonzales, P. Di Nicola, R. M. Franks, A. Nikroo, G. A. Bowers, J. B. McCloud, K. A. Moreno, Nobuhiko Izumi, S. F. Locke, S. A. Vonhof, E. F. Wilson, M. D. Finney, D. P. Atkinson, Damien Hicks, R. Lowe-Webb, R. A. Sacks, B. Riordan, M. Fedorov, A. B. Langdon, Z. Alherz, D. N. Hulsey, E. K. Krieger, S. J. Cohen, T. M. Schindler, B. Burr, J. S. Merill, C. Powell, Pierre Michel, J. S. Zielinski, M. J. Gonzales, C. Marshall, Richard Berger, C. Chan, J. Li, S. L. Townsend, L. Auyang, F. A. Penko, A. D. Casey, C. Chang, D. L. Brinkerhoff, K. M. Knittel, R. J. Strauser, G. Markham, and M. J. Shaw

Subjects
Nuclear physics, Physics, Ignition system, Hohlraum, law, General Physics and Astronomy, Plasma confinement, Magnetic confinement fusion, Plasma, Atomic physics, Radiation, Inertial confinement fusion, law.invention
Published
2011
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14. Demonstration of Ignition Radiation Temperatures in Indirect-Drive Inertial Confinement Fusion Hohlraums

Author

L. V. Berzins, L. M. Kegelmeyer, D. R. Hart, L. J. Suter, M. Shor, Ronald B. Robinson, S. S. Alvarez, G. Gururangan, Robert L. Kauffman, C. T. Warren, R. Darbee, Andrew MacPhee, J. R. Nelson, D. A. Smauley, M. J. Fischer, K. S. Andersson, D. A. Callahan, L. J. Atherton, D. S. Hey, J. D. Kilkenny, T. Ma, J. H. Kamperschroer, T. Frazier, T. J. Clancy, E. A. Williams, P. A. Adams, C. Thai, Laurent Divol, G. J. Edwards, Suhas Bhandarkar, K. Work, M. D. Magat, S. Hunter, Stephen P. Vernon, T. L. Lee, Rolf K. Reed, J.M.Fisher, O. S. Jones, D. Trummer, G. N. Gawinski, G. Antonini, M. P. Johnston, A. J. Mackinnon, M. E. Sheldrick, T. R. Huppler, B. A. Wilson, J. P. Holder, P. L. Stratton, Yiping Chen, J. Jackson, S. Sailors, John Moody, Mark J. Schmitt, L. K. Smith, R. G. Hartley, E. J. Bond, P. Datte, S. Burns, B. McHale, G. Bardsley, D. T. Boyle, D. R. Bopp, E. L. Dewald, J. E. Hamblen, L. Willis, K. G. Krauter, J. R. Schaffer, D. G. Mathisen, M. D. Rosen, J. Morris, M.S.Hutton, G. T. Lau, N. W. Lum, G. Hermes, G. A. Deis, K. N. La Fortune, M. C. Johnson, J. Neumann, C. C. Widmayer, Steven H. Langer, L. F. Finnie, M. C. Witte, K. King, Michael Stadermann, E. A. Stout, M. G. Miller, Wendi Sweet, T. G. Stone, E. A. Tekle, P. M. Danforth, H. Chandrasekaran, D. Larson, M. F. Swisher, J. T. Fink, G. Frieder, L. Bezerides, Kenneth S. Jancaitis, A. L. Throop, B. L. Lechleiter, S. N. Dixit, Kevin S. White, C. Chang, M. K. Shiflett, G. A. Kyrala, F. Stanley, J. Braucht, John Kline, S. M. Gross, A. Baron, R G Beeler, S. Azevedo, R. A. London, T. E. Mills, G Brunton, Marilyn Schneider, M. J. Dailey, R. C. Montesanti, J. Dugorepec, A. J. Churby, I. L. Maslennikov, D. Latray, F. Barbosa, P. A. Arnold, A. A. Marsh, J. J. Rhodes, G. L. Tietbohl, Alexander Thomas, D. B. Dobson, J. M. Tillman, L. L. Silva, G. Erbert, D. A. Barker, R. D. Demaret, J. A. Davis, S. M. Glenn, J. Klingmann, Edward I. Moses, T. M. Pannell, R. T. Shelton, J. M. Di Nicola, N. J. Cahayag, T. Fung, R. L. Rampke, S. Le Pape, Jay D. Salmonson, G. Ross, R. E. Olson, E. Mertens, J. D. Lindl, J. G. Lown, C. M. Estes, A. T. Rivera, Mark W. Bowers, M. Runkel, F. E. Coffield, Wade H. Williams, K. G. Koka, B. A. Hammel, L. M. Burrows, A. S. Rivenes, Daniel H. Kalantar, M. A. Vitalich, M. Y. Mauvais, D. G. Cocherell, J. Grippen, P. V. Amick, B. K. Young, J. G. Soto, A. McGrew, M. J. Edwards, Tilo Döppner, M. J. Christensen, Jeremy Kroll, J. L. Vaher, C. H. Ellerbee, T. N. Malsbury, C. A. Haynam, B. Haid, J. T. Salmon, A. J. van Prooyen, A. L. Warrick, R. Costa, A. V. Hamza, T. G. Parham, C. R. Gibson, S. A. Silva, D. Pendlton, A. W. Huey, P. M. Bell, K. P. Youngblood, B. N. M. Balaoing, Joseph Ralph, R. Rinnert, B Fishler, D. L. Hardy, K. D. Pletcher, J. Liebman, R. K. Butlin, B. Johnson, T. McCarville, L. C. Clowdus, Otto Landen, V. K. Lakamsani, B. P. Golick, F. W. Chambers, D. T. Maloy, D. L. Hipple, C. B. Foxworthy, O. D. Edwards, C. J. Roberts, T. Zaleski, S. C. Burkhart, Thomas J. Johnson, N. Lao, S. R. Marshall, J. A. Baltz, D. E. Speck, R. Miramontes, J. E. Krammen, P. J. van Arsdall, M. A. Bergonia, K. M. Skulina, R. J. Strausser, K. M. Knittel, Siegfried Glenzer, G. J. Mauger, B. E. Smith, Sally Andrews, G. Heestand, P. W. Edwards, E. M. Giraldez, John R. Celeste, N. I. Spafford, R. W. Patterson, J. Watkins, J. B. Tassano, J. C. Ellefson, B. S. Raimondi, Christoph Niemann, M. M. Montoya, M. A. Jackson, T. W. Phillips, H. Gonzales, E. Ng, Mark Eckart, D. M. Lord, S. R. Hahn, L. J. Bernardez, B. D. Cline, A. Forsman, J. W. Florio, D. Pigg, Donald F. Browning, J. L. Vickers, K. M. Morriston, G. A. Keating, G. Pavel, P. C. Dupuy, A. S. Runtal, R. L. Hibbard, P. T. Springer, T. Kohut, B. L. Pepmeier, Richard Town, W. J. Fabyan, S. Huber, A. P. Ludwigsen, G. Holtmeier, D. L. Hodtwalker, M. Neto, P. H. Gschweng, J. D. Moody, K. L. Griffin, B. V. Beeman, J. D. Hollis, E T Alger, G. M. Curnow, P. S. Yang, E. Padilla, M. W. Owens, M. J. Richardson, S. R. Robison, K. Gu, F. J. Lopez, G. Markham, M. J. Shaw, F. E. Wade, R. K. Kirkwood, Pamela K. Whitman, Cliff Thomas, L. F. Alvarez, D. K. Bradley, J. F. Meeker, J. A. Borgman, M. D. Vergino, J. McBride, W. A. Reid, D. E. Petersen, J. S. Taylor, G. T. Villanueva, M. C. Valadez, D. E. Hinkel, M. A. Weingart, K. Charron, S. W. Kramer, R. R. Lyons, S. L. Edson, Klaus Widmann, Q. M. Ngo, H. Zhang, J. B. Alfonso, S. Weaver, J. D. Driscoll, R. M. Marquez, R. M. Franks, A. Nikroo, Mark R. Hermann, R. A. Sacks, Harry B. Radousky, A. B. Langdon, Paul J. Wegner, E. K. Krieger, Pierre Michel, Richard Berger, C. Chan, J. Li, Jose Milovich, J. S. Merill, C. Powell, J. S. Zielinski, L. J. Lagin, S. P. Rogers, J. D. Tappero, N. L. Orsi, S. L. Townsend, L. Auyang, F. A. Penko, V. Rekow, P. G. Zapata, Carlos E. Castro, R. W. Carey, A. D. Casey, K. S. Segraves, D. R. Jedlovec, J. R. Cox, S. Sommer, J. C. Bell, D. L. Brinkerhoff, E. O. Vergel de Dios, G. A. Bowers, R. Zacharias, J. D. Hitchcock, S. W. Lane, R. Prasad, K. A. Moreno, B. J. MacGowan, K. Wilhelmsen, Nobuhiko Izumi, S. F. Locke, R. Chapman, O. R. Rodriguez, S. A. Vonhof, E. F. Wilson, B. L. Olejniczak, G. W. Krauter, R. Lowe-Webb, Nathan Meezan, J. R. Kimbrough, Claire Bishop, D. N. Hulsey, Joseph W. Carlson, R. N. Fallejo, M. J. Gonzalez, L. R. Belk, R. J. Wallace, S. L. Kenitzer, J. Duncan, K. Piston, J. Wen, K. E. Burns, K. L. Tribbey, S. A. Gonzales, J. H. Truong, P. Di Nicola, J. B. McCloud, Y. Lee, S. Shiromizu, T. M. Schindler, B. Burr, R. Saunders, C. Marshall, A. L. Solomon, R. C. Bettenhausen, B. M. Van Wonterghem, H. K. Loey, B. Felker, P. S. Cardinale, M. D. Finney, D. P. Atkinson, Damien Hicks, J. L. Bragg, E. G. Dzenitis, J. A. Robinson, John R. Bower, B. Riordan, S. W. Haan, M. Fedorov, Z. Alherz, S. J. Cohen, A. I. Barnes, A. Y. Chakicherla, and J. L. Reynolds

Subjects
Physics, business.industry, Physics::Optics, General Physics and Astronomy, Implosion, Radiation, Laser, law.invention, Ignition system, Optics, Physics::Plasma Physics, Hohlraum, law, Laser power scaling, Atomic physics, National Ignition Facility, business, Inertial confinement fusion, Astrophysics::Galaxy Astrophysics
Abstract

We demonstrate the hohlraum radiation temperature and symmetry required for ignition-scale inertial confinement fusion capsule implosions. Cryogenic gas-filled hohlraums with 2.2 mm-diameter capsules are heated with unprecedented laser energies of 1.2 MJ delivered by 192 ultraviolet laser beams on the National Ignition Facility. Laser backscatter measurements show that these hohlraums absorb 87% to 91% of the incident laser power resulting in peak radiation temperatures of T(RAD)=300 eV and a symmetric implosion to a 100 μm diameter hot core.

Published
2011
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15. Observation of high soft x-ray drive in large-scale hohlraums at the National Ignition Facility

Author

E. L. Dewald, Denise Hinkel, Cliff Thomas, R G Beeler, John Kline, Otto Landen, B. K. F. Young, J. Liebman, S. Le Pape, B. M. Van Wonterghem, M. D. Rosen, W. W. Hsing, Debra Callahan, C. A. Haynam, Nathan Meezan, J. D. Kilkenny, Daniel H. Kalantar, S. N. Dixit, Siegfried Glenzer, S. Azevedo, John R. Celeste, R. J. Wallace, A. L. Warrick, George A. Kyrala, A. Conder, J. Atherton, D. Larson, B. J. MacGowan, L. J. Suter, J. D. Moody, Robert L. Kauffman, Laurent Divol, E. A. Williams, R. E. Olson, Marilyn Schneider, Klaus Widmann, Pierre Michel, Alastair Moore, and Robert Berger

Subjects
Physics, Radiation flux, Hohlraum, law, General Physics and Astronomy, Plasma, Radiation, Atomic physics, Thermal conduction, National Ignition Facility, Laser, Electromagnetic radiation, law.invention
Abstract

The first soft x-ray radiation flux measurements from hohlraums using both a 96 and a 192 beam configuration at the National Ignition Facility have shown high x-ray conversion efficiencies of {approx}85%-90%. These experiments employed gold vacuum hohlraums, 6.4 mm long and 3.55 mm in diameter, heated with laser energies between 150-635 kJ. The hohlraums reached radiation temperatures of up to 340 eV. These hohlraums for the first time reached coronal plasma conditions sufficient for two-electron processes and coronal heat conduction to be important for determining the radiation drive.

Published
2010

16. Suppression of Stimulated Brillouin Scattering by Increased Landau Damping in Multiple-Ion-Species Hohlraum Plasmas

Author

Laurent Divol, C. Sorce, Dustin Froula, B. J. MacGowan, Siegfried Glenzer, Nathan Meezan, Paul Neumayer, L. J. Suter, Richard Berger, R. A. London, and James Ross

Subjects
Physics, Condensed matter physics, Physics::Optics, General Physics and Astronomy, Plasma, Ion, symbols.namesake, Physics::Plasma Physics, Hohlraum, Brillouin scattering, symbols, Electron temperature, Landau damping, Atomic physics, Rayleigh scattering, Inertial confinement fusion
Abstract

We demonstrate that multiple-ion-species plasmas greatly reduce stimulated Brillouin scattering (SBS) in high-electron temperature inertial confinement fusion hohlraums. Landau damping is increased by adding hydrogen to a ${\mathrm{CO}}_{2}$ gas filled hohlraum. We find that the SBS reflectivity decreases monotonically with increasing hydrogen fraction from 18% to 3% with a simultaneous increase of laser beam transmission. Detailed simulations with a 3D laser-plasma interaction code are in agreement with the experimentally observed reduction in backscattered light.

Published
2008
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17. Green Frequency-Doubled Laser-Beam Propagation in High-Temperature Hohlraum Plasmas

Author

Nathan Meezan, C. Sorce, Christoph Niemann, Siegfried Glenzer, O. S. Jones, Richard Berger, R. K. Kirkwood, James Ross, Dustin Froula, John Moody, L. J. Suter, and Laurent Divol

Subjects
Physics, Coupling, Backscatter, business.industry, General Physics and Astronomy, Magnetic confinement fusion, Plasma, Laser, law.invention, Optics, Physics::Plasma Physics, Hohlraum, law, Electron temperature, business, Inertial confinement fusion
Abstract

We demonstrate propagation and small backscatter losses of a frequency-doubled (2omega) laser beam interacting with inertial confinement fusion hohlraum plasmas. The electron temperature of 3.3 keV, approximately a factor of 2 higher than achieved in previous experiments with open geometry targets, approaches plasma conditions of high-fusion yield hohlraums. In this new temperature regime, we measure 2omega laser-beam transmission approaching 80% with simultaneous backscattering losses of less than 10%. These findings suggest that good laser coupling into fusion hohlraums using 2omega light is possible.

Published
2008
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18. Three-dimensional modeling of stimulated Brillouin scattering in ignition-scale experiments

Author

Nathan Meezan, S. N. Dixit, Laurent Divol, Siegfried Glenzer, L. J. Suter, Dustin Froula, and Richard Berger

Subjects
Physics, business.industry, Scattering, Physics::Optics, General Physics and Astronomy, Fluid mechanics, Polarization (waves), Laser, Computational physics, law.invention, Speckle pattern, symbols.namesake, Optics, Hohlraum, law, Brillouin scattering, symbols, Rayleigh scattering, business
Abstract

The first three-dimensional simulations of a high power 0.351 mum laser beam propagating through a high temperature hohlraum plasma are reported. We show that 3D fluid-based modeling of stimulated Brillouin scattering, including linear kinetic corrections, reproduces quantitatively the experimental measurements, provided it is coupled to detailed hydrodynamics simulation and a realistic description of the laser beam from its millimeter-size envelope down to the micron scale speckles. These simulations accurately predict the strong reduction of stimulated Brillouin scattering measured when polarization smoothing is used.

Published
2007

19. Direct measurements of an increased threshold for stimulated brillouin scattering with polarization smoothing in ignition hohlraum plasmas

Author

R. A. London, Paul Neumayer, David Strozzi, S. Stagnitto, Dustin Froula, L. J. Suter, Richard Berger, Nathan Meezan, Laurent Divol, James Ross, and Siegfried Glenzer

Subjects
Physics, business.industry, General Physics and Astronomy, Plasma, Polarization (waves), symbols.namesake, Optics, Filamentation, Brillouin scattering, Hohlraum, symbols, Atomic physics, Rayleigh scattering, business, Inertial confinement fusion, Smoothing
Abstract

We demonstrate a significant reduction of stimulated Brillouin scattering by polarization smoothing in large-scale high-temperature hohlraum plasma conditions where filamentation is measured to be negligible. The stimulated Brillouin scattering experimental threshold (defined as the intensity at which 5% of the incident light is backscattered) is measured to increase by a factor of $1.7\ifmmode\pm\else\textpm\fi{}0.2$ when polarization smoothing is applied. An analytical model relevant to inertial confinement fusion plasma conditions shows that the measured reduction in backscatter with polarization smoothing results from the random spatial variation in polarization of the laser beam, not from the reduction in beam contrast.

Published
2007

20. Pushing the limits of plasma length in inertial-fusion laser-plasma interaction experiments

Author

Pierre Michel, Richard Berger, P. Neumayer, Jason Ross, Dustin Froula, Siegfried Glenzer, Laurent Divol, R. A. London, Nathan Meezan, and R. J. Wallace

Subjects
Physics, Steady state, Backscatter, General Physics and Astronomy, Plasma, Laser, Omega, law.invention, Physics::Plasma Physics, law, Hohlraum, Atomic physics, Inertial confinement fusion, Energy (signal processing)
Abstract

We demonstrate laser beam propagation and low backscatter in laser produced hohlraum plasmas of ignition plasma length. At intensities I

Published
2007

21. Ideal Laser-Beam Propagation through High-Temperature Ignition Hohlraum Plasmas

Author

James Ross, Paul Neumayer, Laurent Divol, Nathan Meezan, Siegfried Glenzer, John Moody, S. N. Dixit, Dustin Froula, and B. B. Pollock

Subjects
Physics, Electron density, Hohlraum, General Physics and Astronomy, Electron temperature, Plasma, Electron, Atomic physics, Omega, Inertial confinement fusion, Intensity (heat transfer)
Abstract

We demonstrate that a blue ($3\ensuremath{\omega}$, 351 nm) laser beam with an intensity of $2\ifmmode\times\else\texttimes\fi{}{10}^{15}\text{ }\text{ }\mathrm{W}\text{ }{\mathrm{cm}}^{\ensuremath{-}2}$ propagates nearly within the original beam cone through a millimeter scale, ${T}_{e}=3.5\text{ }\text{ }\mathrm{keV}$ high density (${n}_{e}=5\ifmmode\times\else\texttimes\fi{}{10}^{20}\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}3}$) plasma. The beam produced less than 1% total backscatter at these high temperatures and densities; the resulting transmission is greater than 90%. Scaling of the electron temperature in the plasma shows that the plasma becomes transparent for uniform electron temperatures above 3 keV. These results are consistent with linear theory thresholds for both filamentation and backscatter instabilities inferred from detailed hydrodynamic simulations. This provides a strong justification for current inertial confinement fusion designs to remain below these thresholds.

Published
2007
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22. Direct observation of the saturation of stimulated Brillouin scattering by ion-trapping-induced frequency shifts

Author

Gianluca Gregori, C. Niemann, Laurent Divol, A. A. Offenberger, Siegfried Glenzer, Smith Ca, Ao T, Dwight Price, Nathan Meezan, and Dustin Froula

Subjects
Materials science, business.industry, General Physics and Astronomy, Physics::Optics, Plasma, Astrophysics::Cosmology and Extragalactic Astrophysics, Ion trapping, Amplitude, Optics, Brillouin scattering, Physics::Plasma Physics, Plasma diagnostics, Atomic physics, Saturation (chemistry), business, Inertial confinement fusion, Scaling
Abstract

We report the first measurement of the saturation of stimulated Brillouin scattering (SBS) by an ion-trapping-induced frequency shift, which was achieved by directly measuring the amplitude and absolute frequency of SBS-driven ion-acoustic waves (IAW). A frequency shift of up to 30% and a simultaneous saturation of driven IAW and SBS reflectivity were observed. The scaling of the frequency shift with the IAW amplitude compares well with theoretical calculations. We have further measured fast 30 ps oscillations of the SBS-driven IAW amplitude induced by the frequency shift.

Published
2004

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