1
|
Zhang Y, Zhang Z, Yuan X, Glize K, Zhao X, Fang K, Zhang C, Dong Y, Wang S, Bai X, Li B, Liu Z, Wei H, Yuan D, Wu F, Li Y, Zhong J, Li Y, Zhang J. Efficient energy transport throughout conical implosions. Phys Rev E 2024; 109:035205. [PMID: 38632769 DOI: 10.1103/physreve.109.035205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 02/12/2024] [Indexed: 04/19/2024]
Abstract
The double-cone ignition (DCI) scheme has been proposed as one of the alternative approaches to inertial confinement fusion, based on direct-drive and fast-ignition, in order to reduce the requirement for the driver energy. To evaluate the conical implosion energetics from the laser beams to the plasma flows, a series of experiments have been systematically conducted. The results indicate that 89%-96% of the laser energy was absorbed by the target, with moderate stimulated Raman scatterings. Here 2%-6% of the laser energy was coupled into the plasma jets ejected from the cone tips, which was mainly restricted by the mass reductions during the implosions inside the cones. The supersonic dense jets with a Mach number of 4 were obtained, which is favorable for forming a high-density, nondegenerated plasma core after the head-on collisions. These findings show encouraging results in terms of energy transport of the conical implosions in the DCI scheme.
Collapse
Affiliation(s)
- Yihang Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Zhe Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China
- Songshan Lake Materials Laboratory, Dongguan 523808, China
| | - Xiaohui Yuan
- Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China
- MoE Key Laboratory for Laser Plasmas and School of Physics, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Kevin Glize
- Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China
- MoE Key Laboratory for Laser Plasmas and School of Physics, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xu Zhao
- Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China
- MoE Key Laboratory for Laser Plasmas and School of Physics, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ke Fang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Chenglong Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- State Key Laboratory for Tunnel Engineering, China University of Mining and Technology, Beijing 100083, China
| | - Yufeng Dong
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shaojun Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xuejie Bai
- Department of Nuclear Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China
| | - Bingjun Li
- Department of Nuclear Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China
| | - Zhengdong Liu
- Department of Astronomy, Beijing Normal University, Beijing 100875, China
- Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University, Beijing 102206, China
| | - Huigang Wei
- Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China
| | - Dawei Yuan
- Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China
| | - Fuyuan Wu
- Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China
- MoE Key Laboratory for Laser Plasmas and School of Physics, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yanfei Li
- Department of Nuclear Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China
| | - Jiayong Zhong
- Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China
- Department of Astronomy, Beijing Normal University, Beijing 100875, China
- Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University, Beijing 102206, China
| | - Yutong Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China
- Songshan Lake Materials Laboratory, Dongguan 523808, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jie Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China
- MoE Key Laboratory for Laser Plasmas and School of Physics, Shanghai Jiao Tong University, Shanghai 200240, China
| |
Collapse
|
2
|
Liu H, Yang X, Zhang Y, Fang Y, Zhang Z, Yuan X, Li Y, Zhang J. Demonstration of enhanced direct-drive implosion efficiency using gradient pulses. Phys Rev E 2022; 105:L053203. [PMID: 35706321 DOI: 10.1103/physreve.105.l053203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 05/12/2022] [Indexed: 06/15/2023]
Abstract
Higher implosion efficiency is of great significance in direct-drive fusion research. We demonstrated the critical role played by the intensity gradient of the main drive laser pulse in improving efficiency of direct-drive implosions, using a double-gradient nanosecond pulse. Compared with a square pulse, the burn-through depth was increased by over 200%, and the shell velocity was increased by ∼2.1 times with an optimized double-gradient pulse. As the result, the implosion efficiency was enhanced by ∼ six times. It was found that by limiting the intensity gradient of the main drive pulse to no more than ∼2.5×10^{15}W/(cm^{2}ns), heat flux inhibition by nonlocal electron thermal transport effects could be eliminated, and ultimately an efficient mass ablation process was achieved. These results have relevance for pulse designs in ignition-scale direct-drive implosions.
Collapse
Affiliation(s)
- Hao Liu
- Key Laboratory for Laser Plasmas (MoE), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- Collaborative Innovation Centre of IFSA, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiaohu Yang
- Department of Physics, National University of Defense Technology, Changsha 410073, China
- Collaborative Innovation Centre of IFSA, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yihang Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yuan Fang
- Key Laboratory for Laser Plasmas (MoE), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- Collaborative Innovation Centre of IFSA, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zhe Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Collaborative Innovation Centre of IFSA, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiaohui Yuan
- Key Laboratory for Laser Plasmas (MoE), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- Collaborative Innovation Centre of IFSA, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yutong Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Collaborative Innovation Centre of IFSA, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jie Zhang
- Key Laboratory for Laser Plasmas (MoE), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Collaborative Innovation Centre of IFSA, Shanghai Jiao Tong University, Shanghai 200240, China
| |
Collapse
|
3
|
Di Stefano CA, Doss FW, Merritt EC, Haines BM, Desjardins TR, DeVolder BG, Flippo KA, Kot L, Robey HF, Schmidt DW, Millot M. Experimental measurement of two copropagating shocks interacting with an unstable interface. Phys Rev E 2020; 102:043212. [PMID: 33212701 DOI: 10.1103/physreve.102.043212] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 09/10/2020] [Indexed: 11/07/2022]
Abstract
In this work, we present results from experiments capable of producing and measuring the propagation of multiple successive, copropagating shocks across an unstable planar interface, where the shocks are independently driven and separately controllable, enabling the study of this important phenomenon. Copropagating shocks play a significant role in a wide range of systems involving stratified media subject to a shock, and exhibit different physical characteristics compared to counterpropagating shocks. Existing techniques, however, preclude copropagating shocks, so experiments to date have been limited to the study of counterpropagating shocks. We address this previous limitation and open a physical parameter space for study using a new hohlraum platform on the National Ignition Facility. Initial experimental results are presented together with comparisons from numerical simulations.
Collapse
Affiliation(s)
- C A Di Stefano
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - F W Doss
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - E C Merritt
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - B M Haines
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - T R Desjardins
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - B G DeVolder
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - K A Flippo
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - L Kot
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - H F Robey
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - D W Schmidt
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - M Millot
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| |
Collapse
|
4
|
Hill DW, Kingham RJ. Enhancement of pressure perturbations in ablation due to kinetic magnetized transport effects under direct-drive inertial confinement fusion relevant conditions. Phys Rev E 2018; 98:021201. [PMID: 30253597 DOI: 10.1103/physreve.98.021201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Indexed: 06/08/2023]
Abstract
We present kinetic two-dimensional Vlasov-Fokker-Planck simulations, including both self-consistent magnetic fields and ablating ion outflow, of a planar ablating foil subject to nonuniform laser irradiation. Even for small Hall parameters (ωτ_{ei}≲0.05) self-generated magnetic fields are sufficient to invert and enhance pressure perturbations. The mode inversion is caused by a combination of the Nernst advection of the magnetic field and the Righi-Leduc heat flux. Nonlocal effects modify these processes. The mechanism is robust under plasma conditions tested; it is amplitude independent and occurs for a broad spectrum of perturbation wavelengths, λ_{p}=10-100μm. The ablating plasma response to a dynamically evolving speckle pattern perturbation, analogous to an optically smoothed beam, is also simulated. Similar to the single-mode case, self-generated magnetic fields increase the degree of nonuniformity at the ablation surface by up to an order of magnitude and are found to preferentially enhance lower modes due to the resistive damping of high mode number magnetic fields.
Collapse
Affiliation(s)
- D W Hill
- Blackett Laboratory, Imperial College London, Kensington, London SW7 2AZ, United Kingdom
| | - R J Kingham
- Blackett Laboratory, Imperial College London, Kensington, London SW7 2AZ, United Kingdom
| |
Collapse
|
5
|
Rosenberg MJ, Li CK, Fox W, Zylstra AB, Stoeckl C, Séguin FH, Frenje JA, Petrasso RD. Slowing of Magnetic Reconnection Concurrent with Weakening Plasma Inflows and Increasing Collisionality in Strongly Driven Laser-Plasma Experiments. PHYSICAL REVIEW LETTERS 2015; 114:205004. [PMID: 26047236 DOI: 10.1103/physrevlett.114.205004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Indexed: 06/04/2023]
Abstract
An evolution of magnetic reconnection behavior, from fast jets to the slowing of reconnection and the establishment of a stable current sheet, has been observed in strongly driven, β≲20 laser-produced plasma experiments. This process has been inferred to occur alongside a slowing of plasma inflows carrying the oppositely directed magnetic fields as well as the evolution of plasma conditions from collisionless to collisional. High-resolution proton radiography has revealed unprecedented detail of the forced interaction of magnetic fields and super-Alfvénic electron jets (V_{jet}∼20V_{A}) ejected from the reconnection region, indicating that two-fluid or collisionless magnetic reconnection occurs early in time. The absence of jets and the persistence of strong, stable magnetic fields at late times indicates that the reconnection process slows down, while plasma flows stagnate and plasma conditions evolve to a cooler, denser, more collisional state. These results demonstrate that powerful initial plasma flows are not sufficient to force a complete reconnection of magnetic fields, even in the strongly driven regime.
Collapse
Affiliation(s)
- M J Rosenberg
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - C K Li
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - W Fox
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - A B Zylstra
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - C Stoeckl
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - F H Séguin
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - J A Frenje
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - R D Petrasso
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| |
Collapse
|
6
|
Michel DT, Davis AK, Goncharov VN, Sangster TC, Hu SX, Igumenshchev IV, Meyerhofer DD, Seka W, Froula DH. Measurements of the Conduction-Zone Length and Mass Ablation Rate in Cryogenic Direct-Drive Implosions on OMEGA. PHYSICAL REVIEW LETTERS 2015; 114:155002. [PMID: 25933317 DOI: 10.1103/physrevlett.114.155002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Indexed: 06/04/2023]
Abstract
Measurements of the conduction-zone length (110±20 μm at t=2.8 ns), the averaged mass ablation rate of the deuterated plastic (7.95±0.3 μg/ns), shell trajectory, and laser absorption are made in direct-drive cryogenic implosions and are used to quantify the electron thermal transport through the conduction zone. Hydrodynamic simulations that use nonlocal thermal transport and cross-beam energy transfer models reproduce these experimental observables. Hydrodynamic simulations that use a time-dependent flux-limited model reproduce the measured shell trajectory and the laser absorption but underestimate the mass ablation rate by ∼10% and the length of the conduction zone by nearly a factor of 2.
Collapse
Affiliation(s)
- D T Michel
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14636, USA
| | - A K Davis
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14636, USA
| | - V N Goncharov
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14636, USA
| | - T C Sangster
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14636, USA
| | - S X Hu
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14636, USA
| | - I V Igumenshchev
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14636, USA
| | - D D Meyerhofer
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14636, USA
| | - W Seka
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14636, USA
| | - D H Froula
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14636, USA
| |
Collapse
|
7
|
Rosenberg M, Li C, Fox W, Igumenshchev I, Séguin F, Town R, Frenje J, Stoeckl C, Glebov V, Petrasso R. A laboratory study of asymmetric magnetic reconnection in strongly driven plasmas. Nat Commun 2015; 6:6190. [DOI: 10.1038/ncomms7190] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 01/02/2015] [Indexed: 11/09/2022] Open
|
8
|
Hu SX, Collins LA, Boehly TR, Kress JD, Goncharov VN, Skupsky S. First-principles thermal conductivity of warm-dense deuterium plasmas for inertial confinement fusion applications. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:043105. [PMID: 24827353 DOI: 10.1103/physreve.89.043105] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Indexed: 06/03/2023]
Abstract
Thermal conductivity (κ) of both the ablator materials and deuterium-tritium (DT) fuel plays an important role in understanding and designing inertial confinement fusion (ICF) implosions. The extensively used Spitzer model for thermal conduction in ideal plasmas breaks down for high-density, low-temperature shells that are compressed by shocks and spherical convergence in imploding targets. A variety of thermal-conductivity models have been proposed for ICF hydrodynamic simulations of such coupled and degenerate plasmas. The accuracy of these κ models for DT plasmas has recently been tested against first-principles calculations using the quantum molecular-dynamics (QMD) method; although mainly for high densities (ρ > 100 g/cm3), large discrepancies in κ have been identified for the peak-compression conditions in ICF. To cover the wide range of density-temperature conditions undergone by ICF imploding fuel shells, we have performed QMD calculations of κ for a variety of deuterium densities of ρ = 1.0 to 673.518 g/cm3, at temperatures varying from T = 5 × 103 K to T = 8 × 106 K. The resulting κQMD of deuterium is fitted with a polynomial function of the coupling and degeneracy parameters Γ and θ, which can then be used in hydrodynamic simulation codes. Compared with the "hybrid" Spitzer-Lee-More model currently adopted in our hydrocode lilac, the hydrosimulations using the fitted κQMD have shown up to ∼20% variations in predicting target performance for different ICF implosions on OMEGA and direct-drive-ignition designs for the National Ignition Facility (NIF). The lower the adiabat of an imploding shell, the more variations in predicting target performance using κQMD. Moreover, the use of κQMD also modifies the shock conditions and the density-temperature profiles of the imploding shell at early implosion stage, which predominantly affects the final target performance. This is in contrast to the previous speculation that κQMD changes mainly the inside ablation process during the hot-spot formation of an ICF implosion.
Collapse
Affiliation(s)
- S X Hu
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - L A Collins
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - T R Boehly
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - J D Kress
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - V N Goncharov
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - S Skupsky
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| |
Collapse
|
9
|
Hu SX, Fiksel G, Goncharov VN, Skupsky S, Meyerhofer DD, Smalyuk VA. Mitigating laser imprint in direct-drive inertial confinement fusion implosions with high-Z dopants. PHYSICAL REVIEW LETTERS 2012; 108:195003. [PMID: 23003051 DOI: 10.1103/physrevlett.108.195003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Indexed: 06/01/2023]
Abstract
Nonuniformities seeded by both long- and short-wavelength laser perturbations can grow via Rayleigh-Taylor (RT) instability in direct-drive inertial confinement fusion, leading to performance reduction in low-adiabat implosions. To mitigate the effect of laser imprinting on target performance, spherical RT experiments have been performed on OMEGA using Si- or Ge-doped plastic targets in a cone-in-shell configuration. Compared to a pure plastic target, radiation preheating from these high-Z dopants (Si/Ge) increases the ablation velocity and the standoff distance between the ablation front and laser-deposition region, thereby reducing both the imprinting efficiency and the RT growth rate. Experiments showed a factor of 2-3 reduction in the laser-imprinting efficiency and a reduced RT growth rate, leading to significant (3-5 times) reduction in the σ(rms) of shell ρR modulation for Si- or Ge-doped targets. These features are reproduced by radiation-hydrodynamics simulations using the two-dimensional hydrocode DRACO.
Collapse
Affiliation(s)
- S X Hu
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623, USA.
| | | | | | | | | | | |
Collapse
|
10
|
Xu B, Hu SX. Effects of electron-ion temperature equilibration on inertial confinement fusion implosions. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 84:016408. [PMID: 21867323 DOI: 10.1103/physreve.84.016408] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Indexed: 05/31/2023]
Abstract
The electron-ion temperature relaxation essentially affects both the laser absorption in coronal plasmas and the hot-spot formation in inertial confinement fusion (ICF). It has recently been reexamined for plasma conditions closely relevant to ICF implosions using either classical molecular-dynamics simulations or analytical methods. To explore the electron-ion temperature equilibration effects on ICF implosion performance, we have examined two Coulomb logarithm models by implementing them into our hydrocodes, and we have carried out hydrosimulations for ICF implosions. Compared to the Lee-More model that is currently used in our standard hydrocodes, the two models predict substantial differences in laser absorption, coronal temperatures, and neutron yields for ICF implosions at the OMEGA Laser Facility [Boehly et al. Opt. Commun. 133, 495 (1997)]. Such effects on the triple-picket direct-drive design at the National Ignition Facility (NIF) have also been explored. Based on the validity of the two models, we have proposed a combined model of the electron-ion temperature-relaxation rate for the overall ICF plasma conditions. The hydrosimulations using the combined model for OMEGA implosions have shown ∼6% more laser absorption, ∼6%-15% higher coronal temperatures, and ∼10% more neutron yield, when compared to the Lee-More model prediction. It is also noticed that the gain for the NIF direct-drive design can be varied by ∼10% among the different electron-ion temperature-relaxation models.
Collapse
Affiliation(s)
- Barry Xu
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | | |
Collapse
|
11
|
Hu SX, Militzer B, Goncharov VN, Skupsky S. Strong coupling and degeneracy effects in inertial confinement fusion implosions. PHYSICAL REVIEW LETTERS 2010; 104:235003. [PMID: 20867248 DOI: 10.1103/physrevlett.104.235003] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Indexed: 05/29/2023]
Abstract
Accurate knowledge about the equation of state (EOS) of deuterium is critical to inertial confinement fusion (ICF). Low-adiabat ICF implosions routinely access strongly coupled and degenerate plasma conditions. Using the path integral Monte Carlo method, we have derived a first-principles EOS (FPEOS) table of deuterium. It is the first ab initio EOS table which completely covers typical ICF implosion trajectory in the density and temperature ranges of ρ=0.002-1596 g/cm3 and T=1.35 eV-5.5 keV. Discrepancies in internal energy and pressure have been found in strongly coupled and degenerate regimes with respect to SESAME EOS. Hydrodynamics simulations of cryogenic ICF implosions using the FPEOS table have indicated significant differences in peak density, areal density (ρR), and neutron yield relative to SESAME simulations.
Collapse
Affiliation(s)
- S X Hu
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623, USA.
| | | | | | | |
Collapse
|
12
|
Smalyuk VA, Hu SX, Hager JD, Delettrez JA, Meyerhofer DD, Sangster TC, Shvarts D. Rayleigh-Taylor growth measurements in the acceleration phase of spherical implosions on OMEGA. PHYSICAL REVIEW LETTERS 2009; 103:105001. [PMID: 19792320 DOI: 10.1103/physrevlett.103.105001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2009] [Indexed: 05/28/2023]
Abstract
The Rayleigh-Taylor (RT) growth of 3D broadband nonuniformities was measured using x-ray radiography in spherical plastic shells accelerated by laser light at an intensity of approximately 2 x 10(14) W/cm(2). The 20- and 24-microm-thick spherical shells were imploded with 54 beams on the OMEGA laser system. The shells contained diagnostic openings for backlighter x rays used to image shell modulations. The measured shell trajectories and modulation RT growth were in fair agreement with 2D hydro simulations during the acceleration phase of the implosions with convergence ratios of up to approximately 2.2. Since the ignition designs rely on these simulations, improvements in the numerical codes will be implemented to achieve better agreement with experiments.
Collapse
Affiliation(s)
- V A Smalyuk
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | | | | | | | | | | | | |
Collapse
|