Experimental demonstration of early time, hohlraum radiation symmetry tuning for indirect drive ignition experiments

Dewald, E. L.; Milovich, J.; Thomas, C.; Kline, J.; Sorce, C.; Glenn, S.; Landen, O. L.
September 2011
Physics of Plasmas;Sep2011, Vol. 18 Issue 9, p092703
Academic Journal
Early time radiation symmetry at the capsule for indirect drive ignition on the National Ignition Facility (NIF) [G. H. Miller, E. I. Moses, and C. R. Wuest, Nucl. Fusion 44, 228 (2004)] will be inferred from the instantaneous soft x-ray re-emission pattern of a high-Z sphere replacing the ignition capsule. This technique was tested on the OMEGA laser facility [J. M. Soures, R. L. McCrory, T. Boehly et al., Laser Part. Beams 11, 317 (1991)] in near full ignition scale vacuum hohlraums using an equivalent experimental setup to the one planned for NIF. Two laser cones entering each laser entrance hole heat the hohlraums to radiation temperatures of 100 eV, mimicking the NIF ignition pulse foot drive. The experiments have demonstrated accuracies of ±1.5% (±2%) in inferred P2/P0 (P4/P0) Legendre mode incident flux asymmetry and consistency between 900 eV and 1200 eV re-emission patterns. We have also demonstrated the expected tuning capability of P2/P0, from positive (pole hot) to negative (waist hot), decreasing linearly with the inner/outer beams power fraction. P4/P0 on the other hand shows very little variation with power fraction. We developed a simple analytical viewfactor model that is in good agreement with both measured P2/P0 and P4/P0 and their dependence on inner beam power fraction.


Related Articles

  • Early time implosion symmetry from two-axis shock-timing measurements on indirect drive NIF experiments. Moody, J. D.; Robey, H. F.; Celliers, P. M.; Munro, D. H.; Barker, D. A.; Baker, K. L.; Döppner, T.; Hash, N. L.; Hopkins, L. Berzak; LaFortune, K.; Landen, O. L.; LePape, S.; MacGowan, B. J.; Ralph, J. E.; Ross, J. S.; Widmayer, C.; Nikroo, A.; Giraldez, E.; Boehly, T. // Physics of Plasmas;2014, Vol. 21 Issue 9, p1 

    An innovative technique has been developed and used to measure the shock propagation speed along two orthogonal axes in an inertial confinement fusion indirect drive implosion target. This development builds on an existing target and diagnostic platform for measuring the shock propagation along...

  • Stimulated scattering in laser driven fusion and high energy density physics experiments. Yin, L.; Albright, B. J.; Rose, H. A.; Montgomery, D. S.; Kline, J. L.; Kirkwood, R. K.; Milovich, J.; Finnegan, S. M.; Bergen, B.; Bowers, K. J. // Physics of Plasmas;2014, Vol. 21 Issue 9, p1 

    In laser driven fusion and high energy density physics experiments, one often encounters a kkD range of 0.15 < kkD < 0.5, where stimulated Raman scattering (SRS) is active (k is the initial electron plasma wave number and kD is the Debye length). Using particle-in-cell simulations, the SRS...

  • A multi-frame soft x-ray pinhole imaging diagnostic for single-shot applications. Wurden, G. A.; Coffey, S. K. // Review of Scientific Instruments;Oct2012, Vol. 83 Issue 10, p10E516 

    For high energy density magnetized target fusion experiments at the Air Force Research Laboratory FRCHX machine, obtaining multi-frame soft x-ray images of the field reversed configuration (FRC) plasma as it is being compressed will provide useful dynamics and symmetry information. However,...

  • Direct drive implosion experiments on SGIII prototype laser facility: Assessing energy coupling efficiency and implosion symmetry. Yu-dong, Pu; Tian-Xuan, Huang; Huang, Li; Xia-Yu, Zhan; Xiao-Shi, Peng; Tang-Qi; Zi-Feng, Song; Jia-Bin, Chen; Tian-Ming, Song; Ming, Chen; Rui-Zhen, Yu; Xiao-An, He; Chao-Guang, Li; Lu, Zhang; Jia-Hua, Zheng; Long-Fei, Jing; Bo-Lun, Chen; Ming, Su; Wei, Jiang; Bo, Yu // Physics of Plasmas;Jul2012, Vol. 19 Issue 7, p072708 

    Direct drive implosion experiments were conducted on SGIII prototype laser facility. From the time resolved x-ray images, the bright ring and the central bright spot are observed. The radial velocity of the convergent bright ring indicates the shell velocity, and the times when the central...

  • Development of a polar direct-drive platform for studying inertial confinement fusion implosion mix on the National Ignition Facility. Schmitt, Mark J.; Bradley, Paul A.; Cobble, James A.; Fincke, James R.; Hakel, Peter; Hsu, Scott C.; Krasheninnikova, Natalia S.; Kyrala, George A.; Magelssen, Glenn R.; Montgomery, David S.; Murphy, Thomas J.; Obrey, Kimberly A.; Shah, Rahul C.; Tregillis, Ian L.; Baumgaertel, Jessica A.; Wysocki, Frederick J.; Batha, Steven H.; Stephen Craxton, R.; McKenty, Patrick W.; Fitzsimmons, Paul // Physics of Plasmas;May2013, Vol. 20 Issue 5, p056310 

    Experiments were performed to develop a platform for the simultaneous measurement of mix and its effects on fusion burn. Two polar direct drive implosions of all-plastic capsules were conducted for the first time on the National Ignition Facility (NIF). To measure implosion trajectory and...

  • The impact of laser plasma interactions on three-dimensional drive symmetry in inertial confinement fusion implosions. Peterson, J. L.; Michel, P.; Thomas, C. A.; Town, R. P. J. // Physics of Plasmas;Jul2014, Vol. 21 Issue 7, p1 

    Achieving symmetric hohlraum radiation drive is an important aspect of indirectly driven inertial confinement fusion experiments. However, when experimentally delivered laser powers deviate from ideal conditions, the resultant radiation field can become asymmetric. Two situations in which this...

  • Invariance concepts and scalability of two-temperature astrophysical radiating fluids. Falize, E.; Dizière, A.; Loupias, B. // Astrophysics & Space Science;Oct2011, Vol. 336 Issue 1, p201 

    In this work, we present a classification of laboratory astrophysics experiments. We introduce different invariance concepts in order to build scaling laws and to determine the astrophysical relevant of laboratory experiments. Finally we present an analysis of the two-temperature radiating fluid...

  • NIF-scale re-emission sphere measurements of early-time Tr=100 eV hohlraum symmetry (invited). Dewald, E. L.; Thomas, C.; Milovich, J.; Edwards, J.; Sorce, C.; Kirkwood, R.; Meeker, D.; Jones, O.; Izumi, N.; Landen, O. L. // Review of Scientific Instruments;Oct2008, Vol. 79 Issue 10, p10E903 

    The indirect-drive National Ignition Campaign (NIC) proposes to set the first 2 ns of hohlraum radiation symmetry by observing the instantaneous soft x-ray re-emission pattern from a high-Z sphere in place of the ignition capsule. To assess this technique under NIC conditions, we used the Omega...

  • Saturation of multi-laser beams laser-plasma instabilities from stochastic ion heating. Michel, P.; Rozmus, W.; Williams, E. A.; Divol, L.; Berger, R. L.; Glenzer, S. H.; Callahan, D. A. // Physics of Plasmas;May2013, Vol. 20 Issue 5, p056308 

    Cross-beam energy transfer (CBET) has been used as a tool on the National Ignition Facility (NIF) since the first energetics experiments in 2009 to control the energy deposition in ignition hohlraums and tune the implosion symmetry. As large amounts of power are transferred between laser beams...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics