Article
Physics, Fluids & Plasmas
S. Davidovits, C. R. Weber, D. S. Clark
Summary: High-density carbon is a commonly used material in inertial confinement fusion (ICF), and its grain structure can introduce small-scale density inhomogeneity. This study presents a grain model to investigate the impact of de-resolving grains on ICF simulations and demonstrates a simple approach to conserving the deposition of kinetic energy perturbations. The simulations also show the complex interaction between grain-induced mixing and instability, highlighting the role of grain-induced perturbations in enhancing mix penetration in the early stage of shell acceleration.
PHYSICS OF PLASMAS
(2022)
Article
Chemistry, Multidisciplinary
Wu Li, Ruiyang Qu, Weiping Liu, Florian Bourriquen, Stephan Bartling, Nils Rockstroh, Kathrin Junge, Matthias Beller
Summary: The introduction of deuterium atoms into organic compounds is essential for basic chemistry, material sciences, and drug development in the pharmaceutical industry. Researchers have developed a practical and stable heterogeneous copper catalyst for dehalogenative deuteration via water-gas shift reaction at low temperature. This method shows potential for organic synthesis and medicinal chemistry.
Article
Physics, Fluids & Plasmas
M. Rajput, H. L. Swami, S. Vala, M. Abhangi, Ratnesh Kumar, R. Kumar
Summary: In this article, tritium removal from tritium-titanium targets during fusion neutron production and the impact of tritium degradation on neutron production are investigated. The removal of tritium from the target is predicted using the SDTrimSp code. The simulations include ion exchange, sputtering, outgassing of tritium, and thermal diffusion of hydrogen isotopes in the target caused by deuterium irradiation, resulting in nonuniform distribution of tritium in the target. A Python script is developed to study the effects of tritium removal on neutron production.
Article
Physics, Multidisciplinary
Alexandre Do, Christopher R. Weber, Eduard L. Dewald, Daniel T. Casey, Daniel S. Clark, Shahab F. Khan, Otto L. Landen, Andrew G. MacPhee, Vladimir A. Smalyuk
Summary: In indirect-drive inertial confinement fusion experiments, a gentle acceleration of the interface between the capsule ablator and the DT fuel can reduce hydrodynamic instability growth, resulting in improved experimental results.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
D. T. Casey, B. J. MacGowan, J. D. Sater, A. B. Zylstra, O. L. Landen, J. Milovich, O. A. Hurricane, A. L. Kritcher, M. Hohenberger, K. Baker, S. Le Pape, T. Doppner, C. Weber, H. Huang, C. Kong, J. Biener, C. Young, S. Haan, R. C. Nora, S. Ross, H. Robey, M. Stadermann, A. Nikroo, D. A. Callahan, R. M. Bionta, K. D. Hahn, A. S. Moore, D. Schlossberg, M. Bruhn, K. Sequoia, N. Rice, M. Farrell, C. Wild
Summary: In this study, it was found that nonuniformity in the ablator shell thickness in high-density carbon experiments is a significant cause for observed 3D rho R asymmetries, leading to rho R asymmetries of approximately 25% and hot spot velocities of around 100 km/s. This work provides insight into the significant implosion performance degradation in ignition experiments and highlights the need for stringent requirements on capsule thickness metrology and symmetry.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
D. J. Schlossberg, G. P. Grim, D. T. Casey, A. S. Moore, R. Nora, B. Bachmann, L. R. Benedetti, R. M. Bionta, M. J. Eckart, J. E. Field, D. N. Fittinghoff, M. Gatu Johnson, V Geppert-Kleinrath, E. P. Hartouni, R. Hatarik, W. W. Hsing, L. C. Jarrott, S. F. Khan, J. D. Kilkenny, O. L. Landen, B. J. MacGowan, A. J. Mackinnon, K. D. Meaney, D. H. Munro, S. R. Nagel, A. Pak, P. K. Patel, B. K. Spears, P. L. Volegov, C. Young
Summary: Experimental results show that intentionally varying the drive imbalance in inertial confinement fusion implosions can lead to decreased neutron yields and increased anisotropic neutron Doppler broadening, in agreement with simulations. Additionally, a tracer jet from the capsule fill-tube perturbation confirms the average flow speeds deduced from neutron spectroscopy.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Fluids & Plasmas
K. L. Baker, S. MacLaren, O. Jones, B. K. Spears, P. K. Patel, R. Nora, L. Divol, O. L. Landen, G. J. Anderson, J. Gaffney, M. Kruse, O. A. Hurricane, D. A. Callahan, A. R. Christopherson, J. Salmonson, E. P. Hartouni, T. Doppner, E. Dewald, R. Tommasini, C. A. Thomas, C. Weber, D. Clark, D. T. Casey, M. Hohenberger, S. Khan, T. Woods, J. L. Milovich, R. L. Berger, D. Strozzi, A. Kritcher, B. Bachmann, R. Benedetti, R. Bionta, P. M. Celliers, D. Fittinghoff, R. Hatarik, N. Izumi, M. Gatu Johnson, G. Kyrala, T. Ma, K. Meaney, M. Millot, S. R. Nagel, A. Pak, P. L. Volegov, C. Yeamans, C. Wilde
Summary: In order to understand the proximity to ignition of current layered implosions in indirect-drive inertial confinement fusion, the level of alpha heating present needs to be measured. Experimental validation of current simulation-based methods of determining yield amplification was conducted through paired experiments, consisting of low-yield tritium-hydrogen-deuterium (THD) layered implosion and high-yield deuterium-tritium (DT) layered implosion. The THD capsules were designed to reduce DT neutron yield (alpha heating) while maintaining hydrodynamic similarity with the higher yield DT capsules. The measured yield ratio in these experiments allowed the determination of the alpha heating level in the DT layered implosions.
Article
Physics, Fluids & Plasmas
H. Nagatomo, T. Johzaki, M. Hata, Y. Sentoku, S. Fujioka, K. Mima, H. Sakagami
Summary: In this study, an optimal compression method was designed for the fast ignition scheme of laser fusion using a cone-inserted spherical solid target and a multistep laser pulse shape. By considering the scaling law of hydrodynamics, the required laser energy for ignition-scale and burning-scale targets was determined, and a preliminary study of hydrodynamic instability in the optimized implosion design was performed. Additionally, a parameter search was conducted to investigate the feasibility and robustness of high areal density design for changes in the laser pulse shape, with acceptable results for a delay of several tens of picoseconds in the rising laser pulse.
Article
Nuclear Science & Technology
Zhilin Chen, Caifeng Lai, Yu Li, Shenghan Cheng, Yang Yang, Shuming Peng
Summary: The novel Planar-type Ionization Chamber (PIC) detector can measure tritium surface contamination in high gamma dose environments with a low detection limit and high detection efficiency.
FUSION ENGINEERING AND DESIGN
(2021)
Article
Physics, Fluids & Plasmas
A. C. Hayes, G. Kyrala, M. Gooden, J. B. Wilhelmy, L. Kot, P. Volegov, C. Wilde, B. Haines, Gerard Jungman, R. S. Rundberg, D. C. Wilson, C. Velsko, W. Cassata, E. Henry, C. Yeamans, C. Cerjan, T. Ma, T. Doppner, A. Nikroo, O. Hurricane, D. Callahan, D. Hinkel, D. Schneider, B. Bachmann, F. Graziani, K. C. Chen, C. Kong, H. Huang, J. W. Crippen, M. Ratledge, N. G. Rice, M. P. Farrell
Summary: This study reports on the first experiment dedicated to studying nuclear reactions on dopants in a cryogenic capsule at the National Ignition Facility (NIF). Bromine doping in the CH ablator of a capsule, identical to one used in previous NIF shots, was used in the experiment. The results showed that the doped capsule had a DT yield 2.6 times lower than the undoped equivalent. The Radiochemical Analysis of Gaseous Samples (RAGS) system was employed to collect and detect the products of deuteron and proton ion reactions as well as knock-on deuteron reactions.
PHYSICS OF PLASMAS
(2023)
Article
Instruments & Instrumentation
M. Hohenberger, S. Kerr, C. Yeamans, D. Rusby, K. D. Meaney, K. Hahn, R. Heredia, T. Sarginson, B. Blue, A. J. Mackinnon, W. W. Hsing
Summary: A combined environment source utilizing NIF's long-pulse beams and ARC's short pulse lasers was developed for future radiation-effects testing. The platform allows tailored photon and neutron fluences and timing on a recoverable test sample by controlling neutron and x-ray emission separately, exceeding initial fluence goals.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2022)
Article
Physics, Fluids & Plasmas
Masayasu Hata, Takayoshi Sano, Natsumi Iwata, Yasuhiko Sentoku
Summary: Advances in laser technology have led to increased laser intensities, making it necessary to accurately treat the relativistic rising edge component. A double-layer target has been found to improve proton acceleration efficiency, and this design can be optimized using two-dimensional particle-in-cell simulations.
Article
Physics, Fluids & Plasmas
Masayasu Hata, Takayoshi Sano, Natsumi Iwata, Yasuhiko Sentoku
Summary: Advances in laser technology require accurate treatment of the relativistic rising edge component, and double-layer target design enables efficient proton acceleration.
Article
Chemistry, Multidisciplinary
Oscar Suarez-Riano, Gabriel Mencia, Simon Tricard, Jerome Esvan, Pier-Francesco Fazzini, Bruno Chaudret, Edwin A. Baquero
Summary: In this study, a new NHC-stabilized water-soluble Pd/Ni system is presented, which can perform H/D exchange reactions in an enantiospecific manner without reducing the aromatic ring of phenylalanine and tyrosine due to a synergetic Pd-Ni effect.
CHEMICAL COMMUNICATIONS
(2023)
Article
Physics, Multidisciplinary
Zhang Qi, Ma Ji-Rui, Fan Jin-Yan, Zhang Jie
Summary: This paper proposes an optimization method to restore missing NIF experimental data, analyze the design principles of NIF experiments, and predict hot spot pressure. The results may be helpful for the designs of laser fusion ignition experiments in China.
ACTA PHYSICA SINICA
(2022)