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Patel D, Knauer JP, Cao D, Betti R, Nora R, Shvydky A, Gopalaswamy V, Lees A, Sampat S, Donaldson WR, Regan SP, Stoeckl C, Forrest CJ, Glebov VY, Harding DR, Bonino MJ, Janezic RT, Wasilewski D, Fella C, Shuldberg C, Murray J, Guzman D, Serrato B. Effects of Laser Bandwidth in Direct-Drive High-Performance DT-Layered Implosions on the OMEGA Laser. PHYSICAL REVIEW LETTERS 2023; 131:105101. [PMID: 37739360 DOI: 10.1103/physrevlett.131.105101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 07/05/2023] [Accepted: 08/16/2023] [Indexed: 09/24/2023]
Abstract
In direct-drive inertial confinement fusion, the laser bandwidth reduces the laser imprinting seed of hydrodynamic instabilities. The impact of varying bandwidth on the performance of direct-drive DT-layered implosions was studied in targets with different hydrodynamic stability properties. The stability was controlled by changing the shell adiabat from (α_{F}≃5) (more stable) to (α_{F}≃3.5) (less stable). These experiments show that the performance of lower adiabat implosions improves considerably as the bandwidth is raised indicating that further bandwidth increases, beyond the current capabilities of OMEGA, would be greatly beneficial. These results suggest that the future generation of ultra-broadband lasers could enable achieving high convergence and possibly high gains in direct drive ICF.
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Affiliation(s)
- D Patel
- Laboratory for Laser Energetics, University of Rochester, New York 14623, USA
- Department of Mechanical Engineering, University of Rochester, New York 14623, USA
| | - J P Knauer
- Laboratory for Laser Energetics, University of Rochester, New York 14623, USA
| | - D Cao
- Laboratory for Laser Energetics, University of Rochester, New York 14623, USA
| | - R Betti
- Laboratory for Laser Energetics, University of Rochester, New York 14623, USA
- Department of Mechanical Engineering, University of Rochester, New York 14623, USA
- Department of Physics and Astronomy, University of Rochester, New York 14623, USA
| | - R Nora
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - A Shvydky
- Laboratory for Laser Energetics, University of Rochester, New York 14623, USA
| | - V Gopalaswamy
- Laboratory for Laser Energetics, University of Rochester, New York 14623, USA
| | - A Lees
- Laboratory for Laser Energetics, University of Rochester, New York 14623, USA
| | - S Sampat
- Laboratory for Laser Energetics, University of Rochester, New York 14623, USA
| | - W R Donaldson
- Laboratory for Laser Energetics, University of Rochester, New York 14623, USA
| | - S P Regan
- Laboratory for Laser Energetics, University of Rochester, New York 14623, USA
| | - C Stoeckl
- Laboratory for Laser Energetics, University of Rochester, New York 14623, USA
| | - C J Forrest
- Laboratory for Laser Energetics, University of Rochester, New York 14623, USA
| | - V Yu Glebov
- Laboratory for Laser Energetics, University of Rochester, New York 14623, USA
| | - D R Harding
- Laboratory for Laser Energetics, University of Rochester, New York 14623, USA
| | - M J Bonino
- Laboratory for Laser Energetics, University of Rochester, New York 14623, USA
| | - R T Janezic
- Laboratory for Laser Energetics, University of Rochester, New York 14623, USA
| | - D Wasilewski
- Laboratory for Laser Energetics, University of Rochester, New York 14623, USA
| | - C Fella
- Laboratory for Laser Energetics, University of Rochester, New York 14623, USA
| | - C Shuldberg
- General Atomics, San Diego, California 92186, USA
| | - J Murray
- General Atomics, San Diego, California 92186, USA
| | - D Guzman
- General Atomics, San Diego, California 92186, USA
| | - B Serrato
- General Atomics, San Diego, California 92186, USA
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Abstract
Obtaining a burning plasma is a critical step towards self-sustaining fusion energy1. A burning plasma is one in which the fusion reactions themselves are the primary source of heating in the plasma, which is necessary to sustain and propagate the burn, enabling high energy gain. After decades of fusion research, here we achieve a burning-plasma state in the laboratory. These experiments were conducted at the US National Ignition Facility, a laser facility delivering up to 1.9 megajoules of energy in pulses with peak powers up to 500 terawatts. We use the lasers to generate X-rays in a radiation cavity to indirectly drive a fuel-containing capsule via the X-ray ablation pressure, which results in the implosion process compressing and heating the fuel via mechanical work. The burning-plasma state was created using a strategy to increase the spatial scale of the capsule2,3 through two different implosion concepts4-7. These experiments show fusion self-heating in excess of the mechanical work injected into the implosions, satisfying several burning-plasma metrics3,8. Additionally, we describe a subset of experiments that appear to have crossed the static self-heating boundary, where fusion heating surpasses the energy losses from radiation and conduction. These results provide an opportunity to study α-particle-dominated plasmas and burning-plasma physics in the laboratory.
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Christopherson AR, Betti R, Forrest CJ, Howard J, Theobald W, Delettrez JA, Rosenberg MJ, Solodov AA, Stoeckl C, Patel D, Gopalaswamy V, Cao D, Peebles JL, Edgell DH, Seka W, Epstein R, Wei MS, Gatu Johnson M, Simpson R, Regan SP, Campbell EM. Direct Measurements of DT Fuel Preheat from Hot Electrons in Direct-Drive Inertial Confinement Fusion. PHYSICAL REVIEW LETTERS 2021; 127:055001. [PMID: 34397224 DOI: 10.1103/physrevlett.127.055001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 01/02/2021] [Accepted: 06/11/2021] [Indexed: 06/13/2023]
Abstract
Hot electrons generated by laser-plasma instabilities degrade the performance of laser-fusion implosions by preheating the DT fuel and reducing core compression. The hot-electron energy deposition in the DT fuel has been directly measured for the first time by comparing the hard x-ray signals between DT-layered and mass-equivalent ablator-only implosions. The electron energy deposition profile in the fuel is inferred through dedicated experiments using Cu-doped payloads of varying thickness. The measured preheat energy accurately explains the areal-density degradation observed in many OMEGA implosions. This technique can be used to assess the viability of the direct-drive approach to laser fusion with respect to the scaling of hot-electron preheat with laser energy.
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Affiliation(s)
- A R Christopherson
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
- Department of Mechanical Engineering, University of Rochester, Rochester, New York 14623, USA
| | - R Betti
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
- Department of Mechanical Engineering, University of Rochester, Rochester, New York 14623, USA
- Department of Physics and Astronomy, University of Rochester, Rochester, New York 14623, USA
| | - C J Forrest
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - J Howard
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
- Department of Mechanical Engineering, University of Rochester, Rochester, New York 14623, USA
| | - W Theobald
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - J A Delettrez
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - M J Rosenberg
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - A A Solodov
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - C Stoeckl
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - D Patel
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
- Department of Mechanical Engineering, University of Rochester, Rochester, New York 14623, USA
| | - V Gopalaswamy
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
- Department of Mechanical Engineering, University of Rochester, Rochester, New York 14623, USA
| | - D Cao
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - J L Peebles
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - D H Edgell
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - W Seka
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - R Epstein
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - M S Wei
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - M Gatu Johnson
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - R Simpson
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - S P Regan
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - E M Campbell
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
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4
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Campbell EM, Sangster TC, Goncharov VN, Zuegel JD, Morse SFB, Sorce C, Collins GW, Wei MS, Betti R, Regan SP, Froula DH, Dorrer C, Harding DR, Gopalaswamy V, Knauer JP, Shah R, Mannion OM, Marozas JA, Radha PB, Rosenberg MJ, Collins TJB, Christopherson AR, Solodov AA, Cao D, Palastro JP, Follett RK, Farrell M. Direct-drive laser fusion: status, plans and future. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2021; 379:20200011. [PMID: 33280561 PMCID: PMC7741011 DOI: 10.1098/rsta.2020.0011] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/19/2020] [Indexed: 06/12/2023]
Abstract
Laser-direct drive (LDD), along with laser indirect (X-ray) drive (LID) and magnetic drive with pulsed power, is one of the three viable inertial confinement fusion approaches to achieving fusion ignition and gain in the laboratory. The LDD programme is primarily being executed at both the Omega Laser Facility at the Laboratory for Laser Energetics and at the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory. LDD research at Omega includes cryogenic implosions, fundamental physics including material properties, hydrodynamics and laser-plasma interaction physics. LDD research on the NIF is focused on energy coupling and laser-plasma interactions physics at ignition-scale plasmas. Limited implosions on the NIF in the 'polar-drive' configuration, where the irradiation geometry is configured for LID, are also a feature of LDD research. The ability to conduct research over a large range of energy, power and scale size using both Omega and the NIF is a major positive aspect of LDD research that reduces the risk in scaling from OMEGA to megajoule-class lasers. The paper will summarize the present status of LDD research and plans for the future with the goal of ultimately achieving a burning plasma in the laboratory. This article is part of a discussion meeting issue 'Prospects for high gain inertial fusion energy (part 2)'.
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Affiliation(s)
- E. M. Campbell
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - T. C. Sangster
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - V. N. Goncharov
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - J. D. Zuegel
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - S. F. B. Morse
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - C. Sorce
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - G. W. Collins
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - M. S. Wei
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - R. Betti
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - S. P. Regan
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - D. H. Froula
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - C. Dorrer
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - D. R. Harding
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - V. Gopalaswamy
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - J. P. Knauer
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - R. Shah
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - O. M. Mannion
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - J. A. Marozas
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - P. B. Radha
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - M. J. Rosenberg
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - T. J. B. Collins
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - A. R. Christopherson
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - A. A. Solodov
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - D. Cao
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - J. P. Palastro
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - R. K. Follett
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623-1299, USA
| | - M. Farrell
- General Atomics, 3550 General Atomics Court, San Diego, CA, 92121-1122, USA
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