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1. Demonstration of hot-spot fuel gain exceeding unity in direct-drive inertial confinement fusion implosions

Author

Williams, C. A., Betti, R., Gopalaswamy, V., Knauer, J. P., Forrest, C. J., Lees, A., Ejaz, R., Farmakis, P. S., Cao, D., Radha, P. B., Anderson, K. S., Regan, S. P., Glebov, V. Yu, Shah, R. C., Stoeckl, C., Ivancic, S., Churnetski, K., Janezic, R. T., Fella, C., Rosenberg, M. J., Bonino, M. J., Harding, D. R., Shmayda, W. T., Carroll-Nellenback, J., Hu, S. X., Epstein, R., Collins, T. J. B., Thomas, C. A., Igumenshchev, I. V., Goncharov, V. N., Theobald, W., Woo, K. M., Marozas, J. A., Bauer, K. A., Sampat, S., Waxer, L. J., Turnbull, D., Heuer, P. V., McClow, H., Ceurvorst, L., Scullin, W., Edgell, D. H., Koch, M., Bredesen, D., Johnson, M. Gatu, Frenje, J. A., Petrasso, R. D., Shuldberg, C., Farrell, M., Murray, J., Guzman, D., Serrato, B., Morse, S. F. B., Labuzeta, M., Deeney, C., and Campbell, E. M.

Published
2024
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2. Demonstration of a hydrodynamically equivalent burning plasma in direct-drive inertial confinement fusion

Author

Gopalaswamy, V., Williams, C. A., Betti, R., Patel, D., Knauer, J. P., Lees, A., Cao, D., Campbell, E. M., Farmakis, P., Ejaz, R., Anderson, K. S., Epstein, R., Carroll-Nellenbeck, J., Igumenshchev, I. V., Marozas, J. A., Radha, P. B., Solodov, A. A., Thomas, C. A., Woo, K. M., Collins, T. J. B., Hu, S. X., Scullin, W., Turnbull, D., Goncharov, V. N., Churnetski, K., Forrest, C. J., Glebov, V. Yu., Heuer, P. V., McClow, H., Shah, R. C., Stoeckl, C., Theobald, W., Edgell, D. H., Ivancic, S., Rosenberg, M. J., Regan, S. P., Bredesen, D., Fella, C., Koch, M., Janezic, R. T., Bonino, M. J., Harding, D. R., Bauer, K. A., Sampat, S., Waxer, L. J., Labuzeta, M., Morse, S. F. B., Gatu-Johnson, M., Petrasso, R. D., Frenje, J. A., Murray, J., Serrato, B., Guzman, D., Shuldberg, C., Farrell, M., and Deeney, C.

Published
2024
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3. Publisher Correction: Demonstration of a hydrodynamically equivalent burning plasma in direct-drive inertial confinement fusion

Author

Gopalaswamy, V., Williams, C. A., Betti, R., Patel, D., Knauer, J. P., Lees, A., Cao, D., Campbell, E. M., Farmakis, P., Ejaz, R., Anderson, K. S., Epstein, R., Carroll-Nellenbeck, J., Igumenshchev, I. V., Marozas, J. A., Radha, P. B., Solodov, A. A., Thomas, C. A., Woo, K. M., Collins, T. J. B., Hu, S. X., Scullin, W., Turnbull, D., Goncharov, V. N., Churnetski, K., Forrest, C. J., Glebov, V. Yu., Heuer, P. V., McClow, H., Shah, R. C., Stoeckl, C., Theobald, W., Edgell, D. H., Ivancic, S., Rosenberg, M. J., Regan, S. P., Bredesen, D., Fella, C., Koch, M., Janezic, R. T., Bonino, M. J., Harding, D. R., Bauer, K. A., Sampat, S., Waxer, L. J., Labuzeta, M., Morse, S. F. B., Gatu-Johnson, M., Petrasso, R. D., Frenje, J. A., Murray, J., Serrato, B., Guzman, D., Shuldberg, C., Farrell, M., and Deeney, C.

Published
2024
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5. Tripled yield in direct-drive laser fusion through statistical modelling

Author

Gopalaswamy, V., Betti, R., Knauer, J. P., Luciani, N., Patel, D., Woo, K. M., Bose, A., Igumenshchev, I. V., Campbell, E. M., Anderson, K. S., Bauer, K. A., Bonino, M. J., Cao, D., Christopherson, A. R., Collins, G. W., Collins, T. J. B., Davies, J. R., Delettrez, J. A., Edgell, D. H., Epstein, R., Forrest, C. J., Froula, D. H., Glebov, V. Y., Goncharov, V. N., Harding, D. R., Hu, S. X., Jacobs-Perkins, D. W., Janezic, R. T., Kelly, J. H., Mannion, O. M., Maximov, A., Marshall, F. J., Michel, D. T., Miller, S., Morse, S. F. B., Palastro, J., Peebles, J., Radha, P. B., Regan, S. P., Sampat, S., Sangster, T. C., Sefkow, A. B., Seka, W., Shah, R. C., Shmyada, W. T., Shvydky, A., Stoeckl, C., Solodov, A. A., Theobald, W., Zuegel, J. D., Johnson, M. Gatu, Petrasso, R. D., Li, C. K., and Frenje, J. A.

Published
2019
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6. Understanding the fusion yield dependencies in OMEGA DT-layered implosion experiments using a physics-based statistical mapping model

Author

Lees, A., primary, Betti, R., additional, Knauer, J. P., additional, Gopalaswamy, V., additional, Patel, D., additional, Woo, K. M., additional, Anderson, K. S., additional, Campbell, E. M., additional, Cao, D., additional, Carroll-Nellenback, J., additional, Epstein, R., additional, Forrest, C. J., additional, Goncharov, V. N., additional, Harding, D. R., additional, Hu, S. X., additional, Igumenshchev, I. V., additional, Janezic, R. T., additional, Mannion, O. M., additional, Radha, P. B., additional, Regan, S. P., additional, Shvydky, A., additional, Shah, R. C., additional, Shmayda, W. T., additional, Stoeckl, C., additional, Theobald, W., additional, and Thomas, C. A., additional

Published
2023
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7. 3D simulations of inertial confinement fusion implosions part 2: systematic flow anomalies and impact of low modes on performances in OMEGA experiments

Author

Colaïtis, A, primary, Igumenshchev, I V, additional, Turnbull, D P, additional, Shah, R, additional, Edgell, D, additional, Mannion, O M, additional, Stoeckl, C, additional, Jacob-Perkins, D W, additional, Shvydky, A, additional, Janezic, R, additional, Kalb, A, additional, Cao, D, additional, Forrest, C J, additional, Kwiatkowski, J, additional, Regan, S P, additional, Theobald, W, additional, Goncharov, V N, additional, and Froula, D, additional

Published
2022
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8. 3D Simulations Capture the Persistent Low-Mode Asymmetries Evident in Laser-Direct-Drive Implosions on OMEGA

Author

Colaïtis, A., primary, Turnbull, D. P., additional, Igumenschev, I. V., additional, Edgell, D., additional, Shah, R. C., additional, Mannion, O. M., additional, Stoeckl, C., additional, Jacob-Perkins, D., additional, Shvydky, A., additional, Janezic, R., additional, Kalb, A., additional, Cao, D., additional, Forrest, C. J., additional, Kwiatkowski, J., additional, Regan, S., additional, Theobald, W., additional, Goncharov, V. N., additional, and Froula, D. H., additional

Published
2022
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9. Bound on hot-spot mix in high-velocity, high-adiabat direct-drive cryogenic implosions based on comparison of absolute x-ray and neutron yields

Author

Shah, R. C., primary, Cao, D., additional, Aghaian, L., additional, Bachmann, B., additional, Betti, R., additional, Campbell, E. M., additional, Epstein, R., additional, Forrest, C. J., additional, Forsman, A., additional, Glebov, V. Yu., additional, Goncharov, V. N., additional, Gopalaswamy, V., additional, Harding, D. R., additional, Hu, S. X., additional, Igumenshchev, I. V., additional, Janezic, R. T., additional, Keaty, L., additional, Knauer, J. P., additional, Kobs, D., additional, Lees, A., additional, Mannion, O. M., additional, Mohamed, Z. L., additional, Patel, D., additional, Rosenberg, M. J., additional, Shmayda, W. T., additional, Stoeckl, C., additional, Theobald, W., additional, Thomas, C. A., additional, Volegov, P., additional, Woo, K. M., additional, and Regan, S. P., additional

Published
2022
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10. Enhanced laser-energy coupling with small-spot distributed phase plates (SG5-650) in OMEGA DT cryogenic target implosions

Author

Theobald, W., primary, Cao, D., additional, Shah, R. C., additional, Thomas, C. A., additional, Igumenshchev, I. V., additional, Bauer, K. A., additional, Betti, R., additional, Bonino, M. J., additional, Campbell, E. M., additional, Christopherson, A. R., additional, Churnetski, K., additional, Edgell, D. H., additional, Forrest, C. J., additional, Frenje, J. A., additional, Gatu Johnson, M., additional, Glebov, V. Yu., additional, Goncharov, V. N., additional, Gopalaswamy, V., additional, Harding, D. R., additional, Hu, S. X., additional, Ivancic, S. T., additional, Jacobs-Perkins, D. W., additional, Janezic, R. T., additional, Joshi, T., additional, Knauer, J. P., additional, Lees, A., additional, Luo, R. W., additional, Mannion, O. M., additional, Marshall, F. J., additional, Mohamed, Z. L., additional, Morse, S. F. B., additional, Patel, D., additional, Peebles, J. L., additional, Petrasso, R. D., additional, Radha, P. B., additional, Rinderknecht, H. G., additional, Rosenberg, M. J., additional, Sampat, S., additional, Sangster, T. C., additional, Shmayda, W. T., additional, Shuldberg, C. M., additional, Shvydky, A., additional, Sorce, C., additional, Stoeckl, C., additional, Wittman, M. D., additional, and Regan, S. P., additional

Published
2022
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11. Thermal decoupling of deuterium and tritium during the ICF shock-convergence phase

Author

Kabadi, N. V., Simpson, R., Adrian, P. J., Bose, A., Frenje, J. A., Gatu Johnson, M., Lahmann, B., C. K., Li, Parker, C. E., Seguin, F. H., Sutclife, G. D., Petrasso, R. D., Atzeni, S., Eriksson, J., Forrest, C., Fess, S., Yu Glebov, V., Janezic, R., Mannion, O., Rinderknecht, H. G., Rosenberg, M. J., Stoeckl, C., Kagan, G., Hoppe, M., Luo, R., Scho, M., Shuldberg, C., Sio, H. W., Sanchez, J., Berzak Hopkins, L., Schlossberg, D., Hahn, K., and Yeamans, C.

Subjects
inertial confinement fusion, shock-driven implosion, Plasma physics
Published
2021

12. Thermal decoupling of deuterium and tritium during the inertial confinement fusion shock-convergence phase

Author

Kabadi, N. V., primary, Simpson, R., additional, Adrian, P. J., additional, Bose, A., additional, Frenje, J. A., additional, Gatu Johnson, M., additional, Lahmann, B., additional, Li, C. K., additional, Parker, C. E., additional, Séguin, F. H., additional, Sutcliffe, G. D., additional, Petrasso, R. D., additional, Atzeni, S., additional, Eriksson, J., additional, Forrest, C., additional, Fess, S., additional, Glebov, V. Yu, additional, Janezic, R., additional, Mannion, O. M., additional, Rinderknecht, H. G., additional, Rosenberg, M. J., additional, Stoeckl, C., additional, Kagan, G., additional, Hoppe, M., additional, Luo, R., additional, Schoff, M., additional, Shuldberg, C., additional, Sio, H. W., additional, Sanchez, J., additional, Hopkins, L. Berzak, additional, Schlossberg, D., additional, Hahn, K., additional, and Yeamans, C., additional

Published
2021
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13. Thermal decoupling of deuterium and tritium during the inertial confinement fusion shock-convergence phase

Author

V. Kabadi, N., Simpson, R., Adrian, P. J., Bose, A., Frenje, J. A., Johnson, M. Gatu, Lahmann, B., Li, C. K., Parker, C. E., Seguin, F. H., Sutcliffe, G. D., Petrasso, R. D., Atzeni, S., Eriksson, Jacob, Forrest, C., Fess, S., Glebov, V. Yu, Janezic, R., Mannion, O. M., Rinderknecht, H. G., Rosenberg, M. J., Stoeckl, C., Kagan, G., Hoppe, M., Luo, R., Schoff, M., Shuldberg, C., Sio, H. W., Sanchez, J., Hopkins, L. Berzak, Schlossberg, D., Hahn, K., Yeamans, C., V. Kabadi, N., Simpson, R., Adrian, P. J., Bose, A., Frenje, J. A., Johnson, M. Gatu, Lahmann, B., Li, C. K., Parker, C. E., Seguin, F. H., Sutcliffe, G. D., Petrasso, R. D., Atzeni, S., Eriksson, Jacob, Forrest, C., Fess, S., Glebov, V. Yu, Janezic, R., Mannion, O. M., Rinderknecht, H. G., Rosenberg, M. J., Stoeckl, C., Kagan, G., Hoppe, M., Luo, R., Schoff, M., Shuldberg, C., Sio, H. W., Sanchez, J., Hopkins, L. Berzak, Schlossberg, D., Hahn, K., and Yeamans, C.

Abstract

A series of thin glass-shell shock-driven DT gas-filled capsule implosions was conducted at the OMEGA laser facility. These experiments generate conditions relevant to the central plasma during the shock-convergence phase of ablatively driven inertial confinement fusion (ICF) implosions. The spectral temperatures inferred from the DTn and DDn spectra are most consistent with a two-ion-temperature plasma, where the initial apparent temperature ratio, T-T/T-D, is 1.5. This is an experimental confirmation of the long-standing conjecture that plasma shocks couple energy directly proportional to the species mass in multi-ion plasmas. The apparent temperature ratio trend with equilibration time matches expected thermal equilibration described by hydrodynamic theory. This indicates that deuterium and tritium ions have different energy distributions for the time period surrounding shock convergence in ignition-relevant ICF implosions.

Published
2021
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14. Impact of stalk on directly driven inertial confinement fusion implosions

Author

Gatu Johnson, M., primary, Adrian, P. J., additional, Anderson, K. S., additional, Appelbe, B. D., additional, Chittenden, J. P., additional, Crilly, A. J., additional, Edgell, D., additional, Forrest, C. J., additional, Frenje, J. A., additional, Glebov, V. Yu., additional, Haines, B. M., additional, Igumenshchev, I., additional, Jacobs-Perkins, D., additional, Janezic, R., additional, Kabadi, N. V., additional, Knauer, J. P., additional, Lahmann, B., additional, Mannion, O. M., additional, Marshall, F. J., additional, Michel, T., additional, Séguin, F. H., additional, Shah, R., additional, Stoeckl, C., additional, Walsh, C. A., additional, and Petrasso, R. D., additional

Published
2020
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15. Experimental Evidence of a Variant Neutron Spectrum from the $T(t,2n)\alpha$ Reaction at Center-of-Mass Energies in the Range of 16--50 keV

Author

Gatu Johnson, M., Forrest, C.J., Sayre, D.B., Bacher, A., Bourgade, J.L., Brune, C.R., Caggiano, J.A., Casey, D.T., Frenje, J.A., Glebov, V.Yu., Hale, G.M., Hatarik, R., Herrmann, H.W., Janezic, R., Kim, Y.H., Knauer, J.P., Landoas, O., McNabb, D.P., Paris, M.W., Petrasso, R.D., Pino, J.E., Quaglioni, S., Rosse, B., Sanchez, J., Sangster, T.C., Sio, H., Shmayda, W., Stoeckl, C., Thompson, I., Zylstra, A.B., Direction des Applications Militaires (DAM), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment
Abstract

International audience; Full calculations of six-nucleon reactions with a three-body final state have been elusive and a long-standing issue. We present neutron spectra from the T(t,2n)α (TT) reaction measured in inertial confinement fusion experiments at the OMEGA laser facility at ion temperatures from 4 to 18 keV, corresponding to center-of-mass energies (Ec.m.) from 16 to 50 keV. A clear difference in the shape of the TT-neutron spectrum is observed between the two Ec.m., with the He5 ground state resonant peak at 8.6 MeV being significantly stronger at the higher than at the lower energy. The data provide the first conclusive evidence of a variant TT-neutron spectrum in this Ec.m. range. In contrast to earlier available data, this indicates a reaction mechanism that must involve resonances and/or higher angular momenta than L=0. This finding provides an important experimental constraint on theoretical efforts that explore this and complementary six-nucleon systems, such as the solar He3(He3,2p)α reaction.

Published
2018
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16. Impact of imposed mode 2 laser drive asymmetry on inertial confinement fusion implosions

Author

Gatu Johnson, M., primary, Appelbe, B. D., additional, Chittenden, J. P., additional, Crilly, A., additional, Delettrez, J., additional, Forrest, C., additional, Frenje, J. A., additional, Glebov, V. Yu., additional, Grimble, W., additional, Haines, B. M., additional, Igumenshchev, I. V., additional, Janezic, R., additional, Knauer, J. P., additional, Lahmann, B., additional, Marshall, F. J., additional, Michel, T., additional, Séguin, F. H., additional, Stoeckl, C., additional, Walsh, C., additional, Zylstra, A. B., additional, and Petrasso, R. D., additional

Published
2019
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17. Impact of asymmetries on fuel performance in inertial confinement fusion

Author

Gatu Johnson, M., primary, Appelbe, B. D., additional, Chittenden, J. P., additional, Delettrez, J., additional, Forrest, C., additional, Frenje, J. A., additional, Glebov, V. Yu., additional, Grimble, W., additional, Haines, B. M., additional, Igumenshchev, I., additional, Janezic, R., additional, Knauer, J. P., additional, Lahmann, B., additional, Marshall, F. J., additional, Michel, T., additional, Séguin, F. H., additional, Stoeckl, C., additional, Walsh, C., additional, Zylstra, A. B., additional, and Petrasso, R. D., additional

Published
2018
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18. Experimental Evidence of a Variant Neutron Spectrum from the T(t,2n)α Reaction at Center-of-Mass Energies in the Range of 16–50 keV

Author

Gatu Johnson, M., primary, Forrest, C. J., additional, Sayre, D. B., additional, Bacher, A., additional, Bourgade, J.-L., additional, Brune, C. R., additional, Caggiano, J. A., additional, Casey, D. T., additional, Frenje, J. A., additional, Glebov, V. Yu., additional, Hale, G. M., additional, Hatarik, R., additional, Herrmann, H. W., additional, Janezic, R., additional, Kim, Y. H., additional, Knauer, J. P., additional, Landoas, O., additional, McNabb, D. P., additional, Paris, M. W., additional, Petrasso, R. D., additional, Pino, J. E., additional, Quaglioni, S., additional, Rosse, B., additional, Sanchez, J., additional, Sangster, T. C., additional, Sio, H., additional, Shmayda, W., additional, Stoeckl, C., additional, Thompson, I., additional, and Zylstra, A. B., additional

Published
2018
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19. Impact of asymmetries on fuel performance in inertial confinement fusion

Author

Massachusetts Institute of Technology. Department of Nuclear Science and Engineering, Massachusetts Institute of Technology. Plasma Science and Fusion Center, Gatu Johnson, Maria, Frenje, Johan A, Lahmann, Brandon James, Seguin, Fredrick Hampton, Petrasso, Richard D, Appelbe, B. D., Chittenden, J. P., Delettrez, J., Forrest, C., Glebov, V. Yu., Grimble, W., Haines, B. M., Igumenshchev, I., Janezic, R., Knauer, J. P., Marshall, F. J., Michel, T., Stoeckl, C., Walsh, C., Zylstra, A. B., Massachusetts Institute of Technology. Department of Nuclear Science and Engineering, Massachusetts Institute of Technology. Plasma Science and Fusion Center, Gatu Johnson, Maria, Frenje, Johan A, Lahmann, Brandon James, Seguin, Fredrick Hampton, Petrasso, Richard D, Appelbe, B. D., Chittenden, J. P., Delettrez, J., Forrest, C., Glebov, V. Yu., Grimble, W., Haines, B. M., Igumenshchev, I., Janezic, R., Knauer, J. P., Marshall, F. J., Michel, T., Stoeckl, C., Walsh, C., and Zylstra, A. B.

Abstract

Low-mode asymmetries prevent effective compression, confinement, and heating of the fuel in inertial confinement fusion (ICF) implosions, and their control is essential to achieving ignition. Ion temperatures (T[subscript ion]) in ICF experiments are inferred from the broadening of primary neutron spectra. Directional motion (flow) of the fuel at burn also impacts broadening and will lead to artificially inflated “T[subscript ion]” values. Flow due to low-mode asymmetries is expected to give rise to line-of-sight variations in measured T[subscript ion]. We report on intentionally asymmetrically driven experiments at the OMEGA laser facility designed to test the ability to accurately predict and measure line-of-sight differences in apparent T[subscript ion] due to low-mode asymmetry-seeded flows. Contrasted to chimera and xrage simulations, the measurements demonstrate how all asymmetry seeds have to be considered to fully capture the flow field in an implosion. In particular, flow induced by the stalk that holds the target is found to interfere with the seeded asymmetry. A substantial stalk-seeded asymmetry in the areal density of the implosion is also observed., United States. Department of Energy (Award DE-NA0002949)

Published
2018

21. The National Direct-Drive Program: OMEGA to the National Ignition Facility

Author

Regan, S. P., primary, Goncharov, V. N., additional, Sangster, T. C., additional, Campbell, E. M., additional, Betti, R., additional, Anderson, K. S., additional, Bernat, T., additional, Bose, A., additional, Boehly, T. R., additional, Bonino, M. J., additional, Cao, D., additional, Chapman, R., additional, Collins, T. J. B., additional, Craxton, R. S., additional, Davis, A. K., additional, Delettrez, J. A., additional, Edgell, D. H., additional, Epstein, R., additional, Farrell, M., additional, Forrest, C. J., additional, Frenje, J. A., additional, Froula, D. H., additional, Johnson, M. Gatu, additional, Gibson, C., additional, Glebov, V. Yu., additional, Greenwood, A., additional, Harding, D. R., additional, Hohenberger, M., additional, Hu, S. X., additional, Huang, H., additional, Hund, J., additional, Igumenshchev, I. V., additional, Jacobs-Perkins, D. W., additional, Janezic, R. T., additional, Karasik, M., additional, Keck, R. L., additional, Kelly, J. H., additional, Kessler, T. J., additional, Knauer, J. P., additional, Kosc, T. Z., additional, Loucks, S. J., additional, Marozas, J. A., additional, Marshall, F. J., additional, McCrory, R. L., additional, McKenty, P. W., additional, Meyerhofer, D. D., additional, Michel, D. T., additional, Myatt, J. F., additional, Obenschain, S. P., additional, Petrasso, R. D., additional, Petta, N., additional, Radha, P. B., additional, Rosenberg, M. J., additional, Schmitt, A. J., additional, Schmitt, M. J., additional, Schoff, M., additional, Seka, W., additional, Shmayda, W. T., additional, Shoup, M. J., additional, Shvydky, A., additional, Solodov, A. A., additional, Stoeckl, C., additional, Sweet, W., additional, Taylor, C., additional, Taylor, R., additional, Theobald, W., additional, Ulreich, J., additional, Wittman, M. D., additional, Woo, K. M., additional, and Zuegel, J. D., additional

Published
2017
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22. Development of an inertial confinement fusion platform to study charged-particle-producing nuclear reactions relevant to nuclear astrophysics

Author

Gatu Johnson, M., primary, Zylstra, A. B., additional, Bacher, A., additional, Brune, C. R., additional, Casey, D. T., additional, Forrest, C., additional, Herrmann, H. W., additional, Hohenberger, M., additional, Sayre, D. B., additional, Bionta, R. M., additional, Bourgade, J.-L., additional, Caggiano, J. A., additional, Cerjan, C., additional, Craxton, R. S., additional, Dearborn, D., additional, Farrell, M., additional, Frenje, J. A., additional, Garcia, E. M., additional, Glebov, V. Yu., additional, Hale, G., additional, Hartouni, E. P., additional, Hatarik, R., additional, Hohensee, M., additional, Holunga, D. M., additional, Hoppe, M., additional, Janezic, R., additional, Khan, S. F., additional, Kilkenny, J. D., additional, Kim, Y. H., additional, Knauer, J. P., additional, Kohut, T. R., additional, Lahmann, B., additional, Landoas, O., additional, Li, C. K., additional, Marshall, F. J., additional, Masse, L., additional, McEvoy, A., additional, McKenty, P., additional, McNabb, D. P., additional, Nikroo, A., additional, Parham, T. G., additional, Paris, M., additional, Petrasso, R. D., additional, Pino, J., additional, Radha, P. B., additional, Remington, B., additional, Rinderknecht, H. G., additional, Robey, H., additional, Rosenberg, M. J., additional, Rosse, B., additional, Rubery, M., additional, Sangster, T. C., additional, Sanchez, J., additional, Schmitt, M., additional, Schoff, M., additional, Séguin, F. H., additional, Seka, W., additional, Sio, H., additional, Stoeckl, C., additional, and Tipton, R. E., additional

Published
2017
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23. Monochromatic backlighting of direct-drive cryogenic DT implosions on OMEGA

Author

Stoeckl, C., primary, Epstein, R., additional, Betti, R., additional, Bittle, W., additional, Delettrez, J. A., additional, Forrest, C. J., additional, Glebov, V. Yu., additional, Goncharov, V. N., additional, Harding, D. R., additional, Igumenshchev, I. V., additional, Jacobs-Perkins, D. W., additional, Janezic, R. T., additional, Kelly, J. H., additional, Kosc, T. Z., additional, McCrory, R. L., additional, Michel, D. T., additional, Mileham, C., additional, McKenty, P. W., additional, Marshall, F. J., additional, Morse, S. F. B., additional, Regan, S. P., additional, Radha, P. B., additional, Rice, B., additional, Sangster, T. C., additional, Shoup, M. J., additional, Shmayda, W. T., additional, Sorce, C., additional, Theobald, W., additional, Ulreich, J., additional, Wittman, M. D., additional, Meyerhofer, D. D., additional, Frenje, J. A., additional, Gatu Johnson, M., additional, and Petrasso, R. D., additional

Published
2017
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24. Using Inertial Fusion Implosions to Measure the T + [superscript 3]He Fusion Cross Section at Nucleosynthesis-Relevant Energies

Author

Massachusetts Institute of Technology. Department of Physics, Massachusetts Institute of Technology. Plasma Science and Fusion Center, Zylstra, Alex Bennett, Gatu Johnson, Maria, Frenje, Johan A, Li, Chikang, Seguin, Fredrick Hampton, Sio, Hong Weng, Petrasso, Richard D, Herrmann, H. W., Kim, Y. H., Hale, G., Rubery, M., Paris, M., Bacher, A., Brune, C. R., Forrest, C., Glebov, V. Yu., Janezic, R., McNabb, D., Nikroo, A., Pino, J., Sangster, T. C., Seka, W., Stoeckl, C., Massachusetts Institute of Technology. Department of Physics, Massachusetts Institute of Technology. Plasma Science and Fusion Center, Zylstra, Alex Bennett, Gatu Johnson, Maria, Frenje, Johan A, Li, Chikang, Seguin, Fredrick Hampton, Sio, Hong Weng, Petrasso, Richard D, Herrmann, H. W., Kim, Y. H., Hale, G., Rubery, M., Paris, M., Bacher, A., Brune, C. R., Forrest, C., Glebov, V. Yu., Janezic, R., McNabb, D., Nikroo, A., Pino, J., Sangster, T. C., Seka, W., and Stoeckl, C.

Abstract

United States. Department of Energy (DE-NA0001857), United States. Department of Energy (DE-FC52-08NA28752), United States. Department of Energy (DEFG02-88ER40387), United States. Department of Energy (DE-NA0001837), United States. Department of Energy (DE-AC52- 06NA25396), Lawrence Livermore National Laboratory (B597367), Lawrence Livermore National Laboratory (415935- G), University of Rochester. Fusion Science Center (524431), National Laser User’s Facility (DE-NA0002035), National Science Foundation (U.S.). Graduate Research Fellowship Program (Grant 1122374), Los Alamos National Laboratory. Laboratory Directed Research and Development Program (20150717PRD2)

Published
2017

25. Demonstration of Fuel Hot-Spot Pressure in Excess of 50 Gbar for Direct-Drive, Layered Deuterium-Tritium Implosions on OMEGA

Author

Massachusetts Institute of Technology. Plasma Science and Fusion Center, Petrasso, Richard D, Regan, S. P., Goncharov, V. N., Igumenshchev, I. V., Sangster, T. C., Betti, R., Bose, A., Boehly, T. R., Bonino, M. J., Campbell, E. M., Cao, D., Collins, T. J. B., Craxton, R. S., Davis, A. K., Delettrez, J. A., Edgell, D. H., Epstein, R., Forrest, C. J., Frenje, J. A., Froula, D. H., Gatu Johnson, M., Glebov, V. Yu., Harding, D. R., Hohenberger, M., Hu, S. X., Jacobs-Perkins, D., Janezic, R., Karasik, M., Keck, R. L., Kelly, J. H., Kessler, T. J., Knauer, J. P., Kosc, T. Z., Loucks, S. J., Marozas, J. A., Marshall, F. J., McCrory, R. L., McKenty, P. W., Meyerhofer, D. D., Michel, D. T., Myatt, J. F., Obenschain, S. P., Radha, P. B., Rice, B., Rosenberg, M. J., Schmitt, A. J., Schmitt, M. J., Seka, W., Shmayda, W. T., Shoup, M. J., Shvydky, A., Skupsky, S., Solodov, A. A., Stoeckl, C., Theobald, W., Ulreich, J., Wittman, M. D., Woo, K. M., Yaakobi, B., Zuegel, J. D., Massachusetts Institute of Technology. Plasma Science and Fusion Center, Petrasso, Richard D, Regan, S. P., Goncharov, V. N., Igumenshchev, I. V., Sangster, T. C., Betti, R., Bose, A., Boehly, T. R., Bonino, M. J., Campbell, E. M., Cao, D., Collins, T. J. B., Craxton, R. S., Davis, A. K., Delettrez, J. A., Edgell, D. H., Epstein, R., Forrest, C. J., Frenje, J. A., Froula, D. H., Gatu Johnson, M., Glebov, V. Yu., Harding, D. R., Hohenberger, M., Hu, S. X., Jacobs-Perkins, D., Janezic, R., Karasik, M., Keck, R. L., Kelly, J. H., Kessler, T. J., Knauer, J. P., Kosc, T. Z., Loucks, S. J., Marozas, J. A., Marshall, F. J., McCrory, R. L., McKenty, P. W., Meyerhofer, D. D., Michel, D. T., Myatt, J. F., Obenschain, S. P., Radha, P. B., Rice, B., Rosenberg, M. J., Schmitt, A. J., Schmitt, M. J., Seka, W., Shmayda, W. T., Shoup, M. J., Shvydky, A., Skupsky, S., Solodov, A. A., Stoeckl, C., Theobald, W., Ulreich, J., Wittman, M. D., Woo, K. M., Yaakobi, B., and Zuegel, J. D.

Abstract

A record fuel hot-spot pressure P[subscript hs] = 56±7 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 the energy of the National Ignition Facility, these implosions achieved a Lawson parameter ∼60% of the value required for ignition [A. Bose et al., Phys. Rev. E 93, LM15119ER (2016)], similar to indirect-drive implosions [R. Betti et al., Phys. Rev. Lett. 114, 255003 (2015)], and nearly half of the direct-drive ignition-threshold pressure. Relative to symmetric, one-dimensional simulations, the inferred hot-spot pressure is approximately 40% lower. Three-dimensional simulations suggest that low-mode distortion of the hot spot seeded by laser-drive nonuniformity and target-positioning error reduces target performance., United States. Department of Energy (DE-NA0001944)

Published
2017

26. Publisher’s Note: Demonstration of Fuel Hot-Spot Pressure in Excess of 50 Gbar for Direct-Drive, Layered Deuterium-Tritium Implosions on OMEGA [Phys. Rev. Lett.117, 025001 (2016)]

Author

Regan, S. P., primary, Goncharov, V. N., additional, Igumenshchev, I. V., additional, Sangster, T. C., additional, Betti, R., additional, Bose, A., additional, Boehly, T. R., additional, Bonino, M. J., additional, Campbell, E. M., additional, Cao, D., additional, Collins, T. J. B., additional, Craxton, R. S., additional, Davis, A. K., additional, Delettrez, J. A., additional, Edgell, D. H., additional, Epstein, R., additional, Forrest, C. J., additional, Frenje, J. A., additional, Froula, D. H., additional, Gatu Johnson, M., additional, Glebov, V. Yu., additional, Harding, D. R., additional, Hohenberger, M., additional, Hu, S. X., additional, Jacobs-Perkins, D., additional, Janezic, R., additional, Karasik, M., additional, Keck, R. L., additional, Kelly, J. H., additional, Kessler, T. J., additional, Knauer, J. P., additional, Kosc, T. Z., additional, Loucks, S. J., additional, Marozas, J. A., additional, Marshall, F. J., additional, McCrory, R. L., additional, and McKenty, P. W., additional

Published
2016
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27. Using Inertial Fusion Implosions to Measure theT+He3Fusion Cross Section at Nucleosynthesis-Relevant Energies

Author

Zylstra, A. B., primary, Herrmann, H. W., additional, Johnson, M. Gatu, additional, Kim, Y. H., additional, Frenje, J. A., additional, Hale, G., additional, Li, C. K., additional, Rubery, M., additional, Paris, M., additional, Bacher, A., additional, Brune, C. R., additional, Forrest, C., additional, Glebov, V. Yu., additional, Janezic, R., additional, McNabb, D., additional, Nikroo, A., additional, Pino, J., additional, Sangster, T. C., additional, Séguin, F. H., additional, Seka, W., additional, Sio, H., additional, Stoeckl, C., additional, and Petrasso, R. D., additional

Published
2016
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28. Demonstration of Fuel Hot-Spot Pressure in Excess of 50 Gbar for Direct-Drive, Layered Deuterium-Tritium Implosions on OMEGA

Author

Regan, S. P., primary, Goncharov, V. N., additional, Igumenshchev, I. V., additional, Sangster, T. C., additional, Betti, R., additional, Bose, A., additional, Boehly, T. R., additional, Bonino, M. J., additional, Campbell, E. M., additional, Cao, D., additional, Collins, T. J. B., additional, Craxton, R. S., additional, Davis, A. K., additional, Delettrez, J. A., additional, Edgell, D. H., additional, Epstein, R., additional, Forrest, C. J., additional, Frenje, J. A., additional, Froula, D. H., additional, Gatu Johnson, M., additional, Glebov, V. Yu., additional, Harding, D. R., additional, Hohenberger, M., additional, Hu, S. X., additional, Jacobs-Perkins, D., additional, Janezic, R., additional, Karasik, M., additional, Keck, R. L., additional, Kelly, J. H., additional, Kessler, T. J., additional, Knauer, J. P., additional, Kosc, T. Z., additional, Loucks, S. J., additional, Marozas, J. A., additional, Marshall, F. J., additional, McCrory, R. L., additional, McKenty, P. W., additional, Meyerhofer, D. D., additional, Michel, D. T., additional, Myatt, J. F., additional, Obenschain, S. P., additional, Petrasso, R. D., additional, Radha, P. B., additional, Rice, B., additional, Rosenberg, M. J., additional, Schmitt, A. J., additional, Schmitt, M. J., additional, Seka, W., additional, Shmayda, W. T., additional, Shoup, M. J., additional, Shvydky, A., additional, Skupsky, S., additional, Solodov, A. A., additional, Stoeckl, C., additional, Theobald, W., additional, Ulreich, J., additional, Wittman, M. D., additional, Woo, K. M., additional, Yaakobi, B., additional, and Zuegel, J. D., additional

Published
2016
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30. The National Direct-Drive Program: OMEGA to the National Ignition Facility

Author

Regan, S. P., Goncharov, V. N., Sangster, T. C., Campbell, E. M., Betti, R., Anderson, K. S., Bernat, T., Bose, A., Boehly, T. R., Bonino, M. J., Cao, D., Chapman, R., Collins, T. J. B., Craxton, R. S., Davis, A. K., Delettrez, J. A., Edgell, D. H., Epstein, R., Farrell, M., Forrest, C. J., Frenje, J. A., Froula, D. H., Johnson, M. Gatu, Gibson, C., Glebov, V. Yu., Greenwood, A., Harding, D. R., Hohenberger, M., Hu, S. X., Huang, H., Hund, J., Igumenshchev, I. V., Jacobs-Perkins, D. W., Janezic, R. T., Karasik, M., Keck, R. L., Kelly, J. H., Kessler, T. J., Knauer, J. P., Kosc, T. Z., Loucks, S. J., Marozas, J. A., Marshall, F. J., McCrory, R. L., McKenty, P. W., Meyerhofer, D. D., Michel, D. T., Myatt, J. F., Obenschain, S. P., Petrasso, R. D., Petta, N., Radha, P. B., Rosenberg, M. J., Schmitt, A. J., Schmitt, M. J., Schoff, M., Seka, W., Shmayda, W. T., Shoup, M. J., Shvydky, A., Solodov, A. A., Stoeckl, C., Sweet, W., Taylor, C., Taylor, R., Theobald, W., Ulreich, J., Wittman, M. D., Woo, K. M., and Zuegel, J. D.

Abstract

AbstractThe goal of the National Direct-Drive Program is to demonstrate and understand the physics of laser direct drive (LDD). Efforts are underway on OMEGA for the 100-Gbar Campaign to demonstrate and understand the physics for hot-spot conditions and formation relevant for ignition at the 1-MJ scale, and on the National Ignition Facility to develop an understanding of the direct-drive physics at long scale lengths for the MJ Direct-Drive Campaign. The strategy of the National Direct-Drive Program is described; the requirements for the deuterium-tritium cryogenic fill-tube target being developed for OMEGA are presented; and preliminary LDD implosion measurements of hydrodynamic mixing seeded by laser imprint, the target-mounting stalk, and microscopic surface debris are reported.

Published
2018
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32. Cryogenic target-implosion experiments on OMEGA

Author

Harding, D R, primary, Meyerhofer, D D, additional, Sangster, T C, additional, Loucks, S J, additional, McCrory, R L, additional, Betti, R, additional, Delettrez, J A, additional, Edgell, D H, additional, Elasky, L M, additional, Epstein, R, additional, Glebov, V Y, additional, Goncharov, V N, additional, Hu, S X, additional, Igumenshchev, I V, additional, Jacobs-Perkins, D, additional, Janezic, R J, additional, Knauer, J P, additional, Lund, L D, additional, Marciante, J R, additional, Marshall, F J, additional, Maywar, D N, additional, McKenty, P W, additional, Radha, P B, additional, Regan, S P, additional, Roides, R G, additional, Seka, W, additional, Shmayda, W T, additional, Skupsky, S, additional, Smalyuk, V A, additional, Stoeckl, C, additional, Yaakobi, B, additional, Zuegel, J D, additional, Shvartz, D, additional, Frenje, J A, additional, Li, C K, additional, Petrasso, R D, additional, and Séguin, F H, additional

Published
2008
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33. Cryogenic DT and D2 targets for inertial confinement fusion

Author

Sangster, T. C., primary, Betti, R., additional, Craxton, R. S., additional, Delettrez, J. A., additional, Edgell, D. H., additional, Elasky, L. M., additional, Glebov, V. Yu., additional, Goncharov, V. N., additional, Harding, D. R., additional, Jacobs-Perkins, D., additional, Janezic, R., additional, Keck, R. L., additional, Knauer, J. P., additional, Loucks, S. J., additional, Lund, L. D., additional, Marshall, F. J., additional, McCrory, R. L., additional, McKenty, P. W., additional, Meyerhofer, D. D., additional, Radha, P. B., additional, Regan, S. P., additional, Seka, W., additional, Shmayda, W. T., additional, Skupsky, S., additional, Smalyuk, V. A., additional, Soures, J. M., additional, Stoeckl, C., additional, Yaakobi, B., additional, Frenje, J. A., additional, Li, C. K., additional, Petrasso, R. D., additional, Séguin, F. H., additional, Moody, J. D., additional, Atherton, J. A., additional, MacGowan, B. D., additional, Kilkenny, J. D., additional, Bernat, T. P., additional, and Montgomery, D. S., additional

Published
2007
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35. Producing Cryogenic Deuterium Targets for Experiments on OMEGA

Author

Harding, D. R., primary, Sangster, T. C., additional, Meyerhofer, D. D., additional, McKenty, P. W., additional, Lund, L. D., additional, Elasky, L., additional, Wittman, M. D., additional, Seka, W., additional, Loucks, S. J., additional, Janezic, R., additional, Hinterman, T. H., additional, Edgell, D. H., additional, Jacobs-Perkins, D., additional, and Gram, R. Q., additional

Published
2005
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36. Direct-drive, cryogenic target implosions on OMEGA

Author

Marshall, F. J., primary, Craxton, R. S., additional, Delettrez, J. A., additional, Edgell, D. H., additional, Elasky, L. M., additional, Epstein, R., additional, Glebov, V. Yu., additional, Goncharov, V. N., additional, Harding, D. R., additional, Janezic, R., additional, Keck, R. L., additional, Kilkenny, J. D., additional, Knauer, J. P., additional, Loucks, S. J., additional, Lund, L. D., additional, McCrory, R. L., additional, McKenty, P. W., additional, Meyerhofer, D. D., additional, Radha, P. B., additional, Regan, S. P., additional, Sangster, T. C., additional, Seka, W., additional, Smalyuk, V. A., additional, Soures, J. M., additional, Stoeckl, C., additional, Skupsky, S., additional, Frenje, J. A., additional, Li, C. K., additional, Petrasso, R. D., additional, and Séguin, F. H., additional

Published
2005
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38. Improving the hot-spot pressure and demonstrating ignition hydrodynamic equivalence in cryogenic deuterium-tritium implosions on OMEGA.

Author

Goncharov, V. N., Sangster, T. C., Betti, R., Boehly, T. R., Bonino, M. J., Collins, T. J. B., Craxton, R. S., Delettrez, J. A., Edgell, D. H., Epstein, R., Follett, R. K., Forrest, C. J., Froula, D. H., Glebov, V. Yu., Harding, D. R., Henchen, R. J., Hu, S. X., Igumenshchev, I. V., Janezic, R., and Kelly, J. H.

Subjects
HYDRODYNAMICS, LASERS, SIMULATION methods & models, ROBUST control
Abstract

Reaching ignition in direct-drive (DD) inertial confinement fusion implosions requires achieving central pressures in excess of 100 Gbar. The OMEGA laser system [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] is used to study the physics of implosions that are hydrodynamically equivalent to the ignition designs on the National Ignition Facility (NIF) [J. A. Paisner et al., Laser Focus World 30, 75 (1994)]. It is shown that the highest hot-spot pressures (up to 40 Gbar) are achieved in target designs with a fuel adiabat of α~- 4, an implosion velocity of 3.8 × 107 cm/s, and a laser intensity of ~1015 W/cm2. These moderate-adiabat implosions are well understood using two-dimensional hydrocode simulations. The performance of lower-adiabat implosions is significantly degraded relative to code predictions, a common feature between DD implosions on OMEGA and indirect-drive cryogenic implosions on the NIF. Simplified theoretical models are developed to gain physical understanding of the implosion dynamics that dictate the target performance. These models indicate that degradations in the shell density and integrity (caused by hydrodynamic instabilities during the target acceleration) coupled with hydrodynamics at stagnation are the main failure mechanisms in low-adiabat designs. To demonstrate ignition hydrodynamic equivalence in cryogenic implosions on OMEGA, the target-design robustness to hydrodynamic instability growth must be improved by reducing laser-coupling losses caused by cross beam energy transfer. [ABSTRACT FROM AUTHOR]

Published
2014
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41. Cryogenic DT and D2 targets for inertial confinement fusion.

Author

Sangster, T. C., Betti, R., Craxton, R. S., Delettrez, J. A., Edgell, D. H., Elasky, L. M., Glebov, V. Yu., Goncharov, V. N., Harding, D. R., Jacobs-Perkins, D., Janezic, R., Keck, R. L., Knauer, J. P., Loucks, S. J., Lund, L. D., Marshall, F. J., McCrory, R. L., McKenty, P. W., Meyerhofer, D. D., and Radha, P. B.

Subjects
LOW temperature engineering, INERTIAL confinement fusion, DEUTERIUM, TRITIUM, FUEL, ABLATIVE materials
Abstract

Ignition target designs for inertial confinement fusion on the National Ignition Facility (NIF) [W. J. Hogan et al., Nucl. Fusion 41, 567 (2001)] are based on a spherical ablator containing a solid, cryogenic-fuel layer of deuterium and tritium. The need for solid-fuel layers was recognized more than 30 years ago and considerable effort has resulted in the production of cryogenic targets that meet most of the critical fabrication tolerances for ignition on the NIF. At the University of Rochester’s Laboratory for Laser Energetics (LLE), the inner-ice surface of cryogenic DT capsules formed using β-layering meets the surface-smoothness requirement for ignition (<1-μm rms in all modes). Prototype x-ray-drive cryogenic targets being produced at the Lawrence Livermore National Laboratory are nearing the tolerances required for ignition on the NIF. At LLE, these cryogenic DT (and D2) capsules are being imploded on the direct-drive 60-beam, 30-kJ UV OMEGA laser [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. The designs of these cryogenic targets for OMEGA are energy scaled from the baseline direct-drive-ignition design for the NIF. Significant progress with the formation and characterization of cryogenic targets for both direct and x-ray drive will be described. Results from recent cryogenic implosions will also be presented. [ABSTRACT FROM AUTHOR]

Published
2007
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42. Forming cryogenic targets for direct-drive experiments.

Author

Harding, D. R., Meyerhofer, D. D., Loucks, S. J., Lund, L. D., Janezic, R., Elasky, L. M., Hinterman, T. H., Edgell, D. H., Seka, W., Wittman, M. D., Gram, R. Q., Jacobs-Perkins, D., Early, R., Duffy, T., and Bonino, M. J.

Subjects
LOW temperature engineering, DEUTERIUM, FOURIER analysis, POLYCRYSTALS, SURFACE roughness, PHYSICS research
Abstract

More than 100 spherical deuterium ice layers have been formed to make cryogenic targets for direct-drive ICF implosion experiments on OMEGA. These ice layers have an inner surface roughness that ranges from 1.3 to 6μm root-mean-square (rms), with the best layers having a value less than 2 μm rms. These surface roughness values are averaged two-dimensional roughness measurements that cover the entire surface and includes all of the Fourier cosine modes. The ice thickness variation within the layer is predominately in the low spectral modes (mode 5 and lower) and is caused by the support used to hold the target. Changing the design of this support to minimize the thermal effect is constrained by the necessity of having a dynamically stable target for the implosion. We have demonstrated that it is possible to form crystalline ice layers that are facet-free and transparent by slowing the solidification rate of the liquid. Faster freezing rates form layers comprised of polycrystalline ice with a greater roughness (1 to 2 μm greater). Cooling an ice layer 0.5 K below the triple point temperature does not affect the roughness of the layer. Cooling the layer a further 1 K to achieve the desired internal gas pressure sometimes induces additional ice roughness; this roughness is manifest over low- to mid-spectral modes. Removing the thermal shrouds from around the target causes the ice to melt and the internal gas pressure to increase. Using the behavior of a cryogenic deuterium target as a reference, calculations of the response of the more interesting National Ignition Facility-scale deuterium and tritium targets show that exposing the target for 0.8 s to ambient radiation will cause ∼10% of the ice to melt and partially slump whereas the gas pressure will increase by 15%. [ABSTRACT FROM AUTHOR]

Published
2006
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44. Implantable stimulator for selective stimulation of the common peroneal nerve: a preliminary report

Author

Rozman, J., Acimovic-janezic, R., Tekavcic, I., Kljajic, M., and Trlep, M.

Abstract

We present details of the modelling, design, and experimental testing of an implantable system with a monopolar half-cuff electrode for selective stimulation of fibres within certain superficial regions of the human common peroneal nerve which is capable of making a selective activation of muscles, thus contributing to strong dorsal flexion and moderate eversion of the hemiplegic foot. The development of the cuff electrode was based partly on data obtained from histological examination of human common peroneal nerves, and from previously described models of excitation of myelinated nerve fibres. The modelling objectives were to determine the electric field that would be generated within the deep peroneal branch of the nerve by a monopolar half-cuff electrode installed on the nerve behind the lateral head of the fibula. The extent of initial excitation of the nerve fibres within the superficial region of the deep peroneal branch elicited by a monopolar half-cuff electrode was predicted. In the past 6 months two systems were implanted. In both patients significant improvements of gait dynamics were observed.

Published
1994
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45. Chronic electrical stimulation for the modification of spasticity in hemiplegic patients

Author

Aneta Stefanovska, Gros N, Vodovnik L, Rebersek S, and Acimović-Janezic R

Subjects
Adult, Male, Muscle Spasticity, Isometric Contraction, Reflex, Humans, Peroneal Nerve, Electric Stimulation Therapy, Female, Hemiplegia, Middle Aged, Electrodes, Implanted
Abstract

The effects of long-term electrical stimulation on reflex hyperactivity and voluntary muscle control were studied. Eight hemiplegic patients with implanted peroneal stimulator were included. After six months of functional electrical stimulation (FES) there was a decrease of tonic activity in both tibialis anterior and triceps surae muscles. The phasic stretch reflex activity in the stimulated tibialis anterior muscle increased. The resulting resistance during passive movements decreased due to diminution of tonic activity. The absence of tonic activity also resulted in improvement of voluntary control, particularly in the tibialis anterior muscle.

48. Impact of asymmetries on fuel performance in inertial confinement fusion.

Author

Johnson, M. Gatu, Appelbe, B. D., Chittenden, J. P., Delettrez, J., Forrest, C., Frenje, J. A., Glebov, V. Yu., Grimble, W., Haines, B. M., Igumenshchev, I., Janezic, R., Knauer, J. P., Lahmann, B., Marshall, F. J., Michel, T., Séguin, F. H., Stoeckl, C., Walsh, C., Zylstra, A. B., and Petrasso, R. D.

Subjects
*FUEL, *INERTIAL confinement fusion, *COMPRESSION loads
Abstract

Low-mode asymmetries prevent effective compression, confinement, and heating of the fuel in inertial confinement fusion (ICF) implosions, and their control is essential to achieving ignition. Ion temperatures (Tion) in ICF experiments are inferred from the broadening of primary neutron spectra. Directional motion (flow) of the fuel at burn also impacts broadening and will lead to artificially inflated "Tion" values. Flow due to low-mode asymmetries is expected to give rise to line-of-sight variations in measured Tion. We report on intentionally asymmetrically driven experiments at the OMEGA laser facility designed to test the ability to accurately predict and measure line-of-sight differences in apparent Tion due to low-mode asymmetry-seeded flows. Contrasted to chimera and xrage simulations, the measurements demonstrate how all asymmetry seeds have to be considered to fully capture the flow field in an implosion. In particular, flow induced by the stalk that holds the target is found to interfere with the seeded asymmetry. A substantial stalk-seeded asymmetry in the areal density of the implosion is also observed. [ABSTRACT FROM AUTHOR]

Published
2018
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49. Using Inertial Fusion Implosions to Measure the T+³He Fusion Cross Section at Nucleosynthesis-Relevant Energies.

Author

Zylstra, A. B., Herrmann, H. W., Johnson, M. Gatu, Kim, Y. H., Frenje, J. A., Hale, G., Li, C. K., Rubery, M., Paris, M., Bacher, A., Brune, C. R., Forrest, C., Glebov, V. Yu., Janezic, R., McNabb, D., Nikroo, A., Pino, J., Sangster, T. C., Séguin, F. H., and Seka, W.

Subjects
*INERTIAL confinement fusion, *NUCLEAR cross sections, *NUCLEOSYNTHESIS
Abstract

Light nuclei were created during big-bang nucleosynthesis (BBN). Standard BBN theory, using rates inferred from accelerator-beam data, cannot explain high levels of 6Li in low-metallicity stars. Using high-energy-density plasmas we measure the T(³He,γ)6Li reaction rate, a candidate for anomalously high 6Li production; we find that the rate is too low to explain the observations, and different than values used in common BBN models. This is the first data directly relevant to BBN, and also the first use of laboratory plasmas, at comparable conditions to astrophysical systems, to address a problem in nuclear astrophysics. [ABSTRACT FROM AUTHOR]

Published
2016
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50. Applications of a Rayleigh-Taylor model to direct-drive laser fusion.

Author

Thomas CA, Rosenberg MJ, Theobald W, Knauer JP, Stoeckl C, Regan SP, Collins TJB, Goncharov VN, Betti R, Froula D, Deeney C, Anderson KS, Bauer KA, Bonino MJ, Cao D, Craxton RS, Edgell DH, Epstein R, Fess S, Forrest CJ, Glebov VY, Gopalaswamy V, Harding DR, Igumenshchev IV, Ivancic ST, Jacobs-Perkins DW, Janezic RT, Joshi T, Koch M, Kwiatkowski J, Lees A, Marshall FJ, Michalko M, Morse SFB, Patel D, Peebles JL, Radha PB, Rinderknecht HG, Sampat S, Sangster TC, Shah RC, Shmayda WT, Turnbull D, Williams CA, Campbell EM, Christopherson AR, Tabak M, Alexander NB, Farrell MP, and Shuldberg C

Abstract

This paper presents a simple physics-based model for the interpretation of key metrics in laser direct drive. The only input parameters required are target scale, in-flight aspect ratio, and beam-to-target radius, and the importance of each has been quantified with a tailored set of cryogenic implosion experiments. These analyses lead to compact and accurate predictions of the fusion yield and areal density as a function of hydrodynamic stability, and they suggest new ways to take advantage of direct drive. To provide examples, we discuss how the inferred mix width behaves relative to theory and then show how it could be exploited to perform a direct drive implosion with a Lawson metric or χ&#95;{noα} of 0.24±0.02-using a novel parameter space at high velocities and beam radii on the OMEGA laser-that projects to ignition at a laser energy of ≤2.0 MJ.

Published
2024
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