A webinar on Inertial Confinement Fusion was held on Tuesday, September 12th from 11:05 to 12:25 EDT.
Speakers were
Riccardo Betti (Laboratory for Laser Energetics (LLE), University of Rochester) presenting “Progress in Laser Direct-Drive Inertial Confinement Fusion”
and
Benjamin Bachmann (Lawrence Livermore National Laboratory) presenting “National Ignition Facility: Nuclear Fusion Breakthrough”.
Riccardo Betti (PhD) is the Robert L. McCrory Professor of Mechanical Engineering, and Professor of Physics and Astronomy at the University of Rochester. He is also the Chief Scientist of the Laboratory for Laser Energetics. His research involves high temperature plasma physics with applications to nuclear fusion. He served as Chair of the Division of Plasma Physics of the American Physical Society, Vice Chair of the Fusion Energy Science Advisory Committee of the US Department of Energy, Chair of the Plasma Science
Committee of the National Research Council and Member of the Board of Physics and Astronomy of the US National Academy of Science. He received the Blaise Pascal medal by the European Academy of Sciences, the Landau-Spitzer Award from the American and European Physical Societies, the Edward Teller Medal from the American Nuclear Society, the E.O. Lawrence Award from the US Department of Energy, the Leadership Award from Fusion Power Associates, the Lifetime Achievement Award from the UR Hajim School of Engineering and Applied Sciences. He co-authored over 300 peer reviewed papers and supervised over 30 postdoctoral fellows and graduate students. He received his PhD in Nuclear Engineering from the Massachusetts Institute of Technology in 1992.
Progress in Laser Direct-Drive Inertial Confinement Fusion
Recent progress in cryogenic DT-layered implosion experiments on the OMEGA laser have considerably improved the prospects for achieving thermonuclear ignition and energy gains with megajoule-class lasers via direct drive. By hydrodynamically scaling the core conditions of highest performing OMEGA implosions [1], fusion yields above a megajoule are expected for 2 MJ of symmetric laser illumination [2]. Those implosions have benefited from a significant increase in implosion performance obtained through a statistical approach used in predicting implosion experiments and designing targets and laser pulse shapes [3,4] to achieve the highest implosion velocity while maintaining hydrodynamic stability. It is now possible to separate individual contributions to the yield degradation providing a more complete physics picture for each implosion. To test individual degradation mechanisms, dedicated implosion experiments have been carried out by implementing single parameter scans. Scans of the SSD (Smoothing by Spectral Dispersion) bandwidth [5,6] to study laser imprinting; scans of the stalk mount
size are used to study effects of engineering features; scans of the vapor pressure are used to study the effects of higher implosion convergence. An overview of the implosion optimization effort and of the dedicated physics experiments at the OMEGA laser will be provided.
References
[1] C.A. Williams et al, submitted to Nature Physics (2023); C.A. Williams at this conference.
[2] V. Gopalaswamy et al, submitted to Nature Physics (2023);
[3] V. Gopalaswamy et al, Nature 565, 581-586 (2019)
[4] A. Lees et al, Phys. Rev. Lett. 125, 105001 (2021); A. Lees at this conference
[5] D. Patel et al, Submitted to Phys. Rev. Lett. (2023)
[6] J.P. Knauer et al, Bulletin American Physical Society, Invited Presentation NI02.00002, (2022)
*This material is based upon work supported by the Department of Energy Office of Fusion Energy Sciences under award DE-SC0022132, the National Nuclear Security Administration under Award Numbers DE-NA0003856, DENA0003868, the University of Rochester, and the New York State Energy Research and Development Authority. In collaboration with the LLE Experimental and Theory Divisions, the OMEGA facility team, the LLE Target Fabrication group, the LLE Cryogenic and Tritium group, the General Atomics target fabrication group and the HEDP Division at the MIT-PFSC.
Benjamin Bachmann (PhD) is a physicist at Lawrence Livermore National Laboratory (LLNL) with research focus on the capsule and stagnation physics in Inertial Confinement Fusion (ICF). Benjamin received his doctoral degree in plasma physics from the University of the German Federal Armed Forces in 2013 and subsequently joined LLNL. Since then, Benjamin has developed x-ray imaging and analysis techniques to measure thermophysical properties of ICF plasmas and led various experimental campaigns to understand mix and hydrodynamic instabilities seeded in ICF capsules. Benjamin is part of the NIF Ignition Team and the leader of the Hotspot Reconstruction and Diffuse Mix Group that analyzes ignition experiments at the National Ignition Facility. He is the recipient of two U.S. Department of Energy Secretary’s Honors awards and received the 2022 John Dawson award for Excellence in Plasma Physics Research from the American Physical Society.
National Ignition Facility: Nuclear Fusion Breakthrough
Groundbreaking advancements have been made in Inertial Confinement Fusion (ICF) research at the National Ignition Facility (NIF), resulting in experiments that have surpassed Lawson’s criterion and have demonstrated a gain (G) greater than unity [1]. Improving the gain in ICF requires achieving higher areal densities, exceeding 1.5 g/cm2, assembled via spherical compression to confine the fuel while the thermonuclear burn wave consumes more than 10% of the deuterium-tritium fuel. In this presentation, we will provide an overview of the ICF implosions that have achieved ignition on the NIF. Additionally, we will delve into the ongoing efforts to increase compression in ICF experiments to attain even higher gains (G >> 1).
References
[1] H. Abu-Shawareb et al., PRL 129, 075001 (2022).
* This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
