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Start Over Author "Ralph, J. E." Publication Type Electronic Resources
3 results on '"Ralph, J. E."'

1. Experiments conducted in the burning plasma regime with inertial fusion implosions

Author

Ross, J. S., Ralph, J. E., Zylstra, A. B., Kritcher, A. L., Robey, H. F., Young, C. V., Hurricane, O. A., Callahan, D. A., Baker, K. L., Casey, D. T., Doeppner, T., Divol, L., Hohenberger, M., Pape, S. Le, Pak, A., Patel, P. K., Tommasini, R., Ali, S. J., Amendt, P. A., Atherton, L. J., Bachmann, B., Bailey, D., Benedetti, L. R., Hopkins, L. Berzak, Betti, R., Bhandarkar, S. D., Bionta, R. M., Birge, N. W., Bond, E. J., Bradley, D. K., Braun, T., Briggs, T. M., Bruhn, M. W., Celliers, P. M., Chang, B., Chapman, T., Chen, H., Choate, C., Christopherson, A. R., Clark, D. S., Crippen, J. W., Dewald, E. L., Dittrich, T. R., Edwards, M. J., Farmer, W. A., Field, J. E., Fittinghoff, D., Frenje, J., Gaffney, J., Johnson, M. Gatu, Glenzer, S. H., Grim, G. P., Haan, S., Hahn, K. D., Hall, G. N., Hammel, B. A., Harte, J., Hartouni, E., Heebner, J. E., Hernandez, V. J., Herrmann, H., Herrmann, M. C., Hinkel, D. E., Ho, D. D., Holder, J. P., Hsing, W. W., Huang, H., Humbird, K. D., Izumi, N., Jarrott, L. C., Jeet, J., Jones, O., Kerbel, G. D., Kerr, S. M., Khan, S. F., Kilkenny, J., Kim, Y., Kleinrath, H. Geppert, Kleinrath, V. Geppert, Kong, C., Koning, J. M., Kroll, J. J., Landen, O. L., Langer, S., Larson, D., Lemos, N. C., Lindl, J. D., Ma, T., MacDonald, M. J., MacGowan, B. J., Mackinnon, A. J., MacLaren, S. A., MacPhee, A. G., Marinak, M. M., Mariscal, D. A., Marley, E. V., Masse, L., Meaney, K., Meezan, N. B., Michel, P. A., Millot, M., Milovich, J. L., Moody, J. D., Moore, A. S., Morton, J. W., Murphy, T., Newman, K., Di Nicola, J. -M. G., Nikroo, A., Nora, R., Patel, M. V., Pelz, L. J., Peterson, J. L., Ping, Y., Pollock, B. B., Ratledge, M., Rice, N. G., Rinderknecht, H., Rosen, M., Rubery, M. S., Salmonson, J. D., Sater, J., Schiaffino, S., Schlossberg, D. J., Schneider, M. B., Schroeder, C. R., Scott, H. A., Sepke, S. M., Sequoia, K., Sherlock, M. W., Shin, S., Smalyuk, V. A., Spears, B. K., Springer, P. T., Stadermann, M., Stoupin, S., Strozzi, D. J., Suter, L. J., Thomas, C. A., Town, R. P. J., Tubman, E. R., Volegov, P. L., Weber, C. R., Widmann, K., Wild, C., Wilde, C. H., Van Wonterghem, B. M., Woods, D. T., Woodworth, B. N., Yamaguchi, M., Yang, S. T., Zimmerman, G. B., Ross, J. S., Ralph, J. E., Zylstra, A. B., Kritcher, A. L., Robey, H. F., Young, C. V., Hurricane, O. A., Callahan, D. A., Baker, K. L., Casey, D. T., Doeppner, T., Divol, L., Hohenberger, M., Pape, S. Le, Pak, A., Patel, P. K., Tommasini, R., Ali, S. J., Amendt, P. A., Atherton, L. J., Bachmann, B., Bailey, D., Benedetti, L. R., Hopkins, L. Berzak, Betti, R., Bhandarkar, S. D., Bionta, R. M., Birge, N. W., Bond, E. J., Bradley, D. K., Braun, T., Briggs, T. M., Bruhn, M. W., Celliers, P. M., Chang, B., Chapman, T., Chen, H., Choate, C., Christopherson, A. R., Clark, D. S., Crippen, J. W., Dewald, E. L., Dittrich, T. R., Edwards, M. J., Farmer, W. A., Field, J. E., Fittinghoff, D., Frenje, J., Gaffney, J., Johnson, M. Gatu, Glenzer, S. H., Grim, G. P., Haan, S., Hahn, K. D., Hall, G. N., Hammel, B. A., Harte, J., Hartouni, E., Heebner, J. E., Hernandez, V. J., Herrmann, H., Herrmann, M. C., Hinkel, D. E., Ho, D. D., Holder, J. P., Hsing, W. W., Huang, H., Humbird, K. D., Izumi, N., Jarrott, L. C., Jeet, J., Jones, O., Kerbel, G. D., Kerr, S. M., Khan, S. F., Kilkenny, J., Kim, Y., Kleinrath, H. Geppert, Kleinrath, V. Geppert, Kong, C., Koning, J. M., Kroll, J. J., Landen, O. L., Langer, S., Larson, D., Lemos, N. C., Lindl, J. D., Ma, T., MacDonald, M. J., MacGowan, B. J., Mackinnon, A. J., MacLaren, S. A., MacPhee, A. G., Marinak, M. M., Mariscal, D. A., Marley, E. V., Masse, L., Meaney, K., Meezan, N. B., Michel, P. A., Millot, M., Milovich, J. L., Moody, J. D., Moore, A. S., Morton, J. W., Murphy, T., Newman, K., Di Nicola, J. -M. G., Nikroo, A., Nora, R., Patel, M. V., Pelz, L. J., Peterson, J. L., Ping, Y., Pollock, B. B., Ratledge, M., Rice, N. G., Rinderknecht, H., Rosen, M., Rubery, M. S., Salmonson, J. D., Sater, J., Schiaffino, S., Schlossberg, D. J., Schneider, M. B., Schroeder, C. R., Scott, H. A., Sepke, S. M., Sequoia, K., Sherlock, M. W., Shin, S., Smalyuk, V. A., Spears, B. K., Springer, P. T., Stadermann, M., Stoupin, S., Strozzi, D. J., Suter, L. J., Thomas, C. A., Town, R. P. J., Tubman, E. R., Volegov, P. L., Weber, C. R., Widmann, K., Wild, C., Wilde, C. H., Van Wonterghem, B. M., Woods, D. T., Woodworth, B. N., Yamaguchi, M., Yang, S. T., and Zimmerman, G. B.

Abstract

An experimental program is currently underway at the National Ignition Facility (NIF) to compress deuterium and tritium (DT) fuel to densities and temperatures sufficient to achieve fusion and energy gain. The primary approach being investigated is indirect drive inertial confinement fusion (ICF), where a high-Z radiation cavity (a hohlraum) is heated by lasers, converting the incident energy into x-ray radiation which in turn drives the DT fuel filled capsule causing it to implode. Previous experiments reported DT fuel gain exceeding unity [O.A. Hurricane et al., Nature 506, 343 (2014)] and then exceeding the kinetic energy of the imploding fuel [S. Le Pape et al., Phys. Rev. Lett. 120, 245003 (2018)]. We report on recent experiments that have achieved record fusion neutron yields on NIF, greater than 100 kJ with momentary fusion powers exceeding 1PW, and have for the first time entered the burning plasma regime where fusion alpha-heating of the fuel exceeds the energy delivered to the fuel via compression. This was accomplished by increasing the size of the high-density carbon (HDC) capsule, increasing energy coupling, while controlling symmetry and implosion design parameters. Two tactics were successful in controlling the radiation flux symmetry and therefore the implosion symmetry: transferring energy between laser cones via plasma waves, and changing the shape of the hohlraum. In conducting these experiments, we controlled for known sources of degradation. Herein we show how these experiments were performed to produce record performance, and demonstrate the data fidelity leading us to conclude that these shots have entered the burning plasma regime.

Published
2021

2. Indications of flow near maximum compression in layered deuterium-tritium implosions at the National Ignition Facility

Author

Massachusetts Institute of Technology. Plasma Science and Fusion Center, Gatu Johnson, Maria, Frenje, Johan A, Petrasso, Richard D, Knauer, J. P., Cerjan, C. J., Eckart, M. J., Grim, G. P., Hartouni, E. P., Hatarik, R., Kilkenny, J. D., Munro, D. H., Sayre, D. B., Spears, B. K., Bionta, R. M., Bond, E. J., Caggiano, J. A., Callahan, D., Casey, D. T., Döppner, T., Glebov, V. Yu., Hurricane, O., Kritcher, A., LePape, S., Ma, T., Mackinnon, A., Meezan, N., Patel, P., Ralph, J. E., Springer, P. T., Yeamans, C. B., Massachusetts Institute of Technology. Plasma Science and Fusion Center, Gatu Johnson, Maria, Frenje, Johan A, Petrasso, Richard D, Knauer, J. P., Cerjan, C. J., Eckart, M. J., Grim, G. P., Hartouni, E. P., Hatarik, R., Kilkenny, J. D., Munro, D. H., Sayre, D. B., Spears, B. K., Bionta, R. M., Bond, E. J., Caggiano, J. A., Callahan, D., Casey, D. T., Döppner, T., Glebov, V. Yu., Hurricane, O., Kritcher, A., LePape, S., Ma, T., Mackinnon, A., Meezan, N., Patel, P., Ralph, J. E., Springer, P. T., and Yeamans, C. B.

Abstract

An accurate understanding of burn dynamics in implosions of cryogenically layered deuterium (D) and tritium (T) filled capsules, obtained partly through precision diagnosis of these experiments, is essential for assessing the impediments to achieving ignition at the National Ignition Facility. We present measurements of neutrons from such implosions. The apparent ion temperatures T[subscript ion] are inferred from the variance of the primary neutron spectrum. Consistently higher DT than DD T[subscript ion] are observed and the difference is seen to increase with increasing apparent DT T[subscript ion]. The line-of-sight rms variations of both DD and DT T[subscript ion] are small, ∼ 150 eV, indicating an isotropic source. The DD neutron yields are consistently high relative to the DT neutron yields given the observed T[subscript ion]. Spatial and temporal variations of the DT temperature and density, DD-DT differential attenuation in the surrounding DT fuel, and fluid motion variations contribute to a DT T[subscript ion] greater than the DD T[subscript ion], but are in a one-dimensional model insufficient to explain the data. We hypothesize that in a three-dimensional interpretation, these effects combined could explain the results., Lawrence Livermore National Laboratory (Contract No. DE-AC52- 07NA27344)

Published
2017

3. Demonstration of High Performance in Layered Deuterium-Tritium Capsule Implosions in Uranium Hohlraums at the National Ignition Facility

Author

Massachusetts Institute of Technology. Plasma Science and Fusion Center, Frenje, Johan A., Gatu Johnson, Maria, Doppner, T., Callahan, D. A., Hurricane, O. A., Hinkel, D. E., Ma, T., Park, H.-S., Berzak Hopkins, L. F., Casey, D. T., Celliers, P., Dewald, E. L., Dittrich, T. R., Haan, S. W., Kritcher, A. L., MacPhee, A. G., Le Pape, S., Pak, A., Patel, P. K., Springer, P. T., Salmonson, J. D., Tommasini, R., Benedetti, L. R., Bond, E., Bradley, D. K., Caggiano, J., Church, J., Dixit, S., Edgell, D., Edwards, M. J., Fittinghoff, D. N., Grim, G., Hatarik, R., Havre, M., Herrmann, H., Izumi, N., Khan, S. F., Kline, J. L., Knauer, J., Kyrala, G. A., Landen, O. L., Merrill, F. E., Moody, J. D., Moore, A. S., Nikroo, A., Ralph, J. E., Remington, B. A., Robey, H. F., Sayre, D., Schneider, M., Streckert, H., Town, R., Turnbull, D., Volegov, P. L., Wan, A., Widmann, K., Wilde, C. H., Yeamans, C., Massachusetts Institute of Technology. Plasma Science and Fusion Center, Frenje, Johan A., Gatu Johnson, Maria, Doppner, T., Callahan, D. A., Hurricane, O. A., Hinkel, D. E., Ma, T., Park, H.-S., Berzak Hopkins, L. F., Casey, D. T., Celliers, P., Dewald, E. L., Dittrich, T. R., Haan, S. W., Kritcher, A. L., MacPhee, A. G., Le Pape, S., Pak, A., Patel, P. K., Springer, P. T., Salmonson, J. D., Tommasini, R., Benedetti, L. R., Bond, E., Bradley, D. K., Caggiano, J., Church, J., Dixit, S., Edgell, D., Edwards, M. J., Fittinghoff, D. N., Grim, G., Hatarik, R., Havre, M., Herrmann, H., Izumi, N., Khan, S. F., Kline, J. L., Knauer, J., Kyrala, G. A., Landen, O. L., Merrill, F. E., Moody, J. D., Moore, A. S., Nikroo, A., Ralph, J. E., Remington, B. A., Robey, H. F., Sayre, D., Schneider, M., Streckert, H., Town, R., Turnbull, D., Volegov, P. L., Wan, A., Widmann, K., Wilde, C. H., and Yeamans, C.

Abstract

We report on the first layered deuterium-tritium (DT) capsule implosions indirectly driven by a “high-foot” laser pulse that were fielded in depleted uranium hohlraums at the National Ignition Facility. Recently, high-foot implosions have demonstrated improved resistance to ablation-front Rayleigh-Taylor instability induced mixing of ablator material into the DT hot spot [Hurricane et al., Nature (London) 506, 343 (2014)]. Uranium hohlraums provide a higher albedo and thus an increased drive equivalent to an additional 25 TW laser power at the peak of the drive compared to standard gold hohlraums leading to higher implosion velocity. Additionally, we observe an improved hot-spot shape closer to round which indicates enhanced drive from the waist. In contrast to findings in the National Ignition Campaign, now all of our highest performing experiments have been done in uranium hohlraums and achieved total yields approaching 10[superscript 16] neutrons where more than 50% of the yield was due to additional heating of alpha particles stopping in the DT fuel., United States. Dept. of Energy (Lawrence Livermore National Laboratory Contract DE-AC52-07NA27344)

Published
2015

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