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Turnbull D, Katz J, Sherlock M, Divol L, Shaffer NR, Strozzi DJ, Colaïtis A, Edgell DH, Follett RK, McMillen KR, Michel P, Milder AL, Froula DH. Inverse Bremsstrahlung Absorption. PHYSICAL REVIEW LETTERS 2023; 130:145103. [PMID: 37084458 DOI: 10.1103/physrevlett.130.145103] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 03/20/2023] [Indexed: 05/03/2023]
Abstract
Inverse bremsstrahlung absorption was measured based on transmission through a finite-length plasma that was thoroughly characterized using spatially resolved Thomson scattering. Expected absorption was then calculated using the diagnosed plasma conditions while varying the absorption model components. To match data, it is necessary to account for (i) the Langdon effect; (ii) laser-frequency (rather than plasma-frequency) dependence in the Coulomb logarithm, as is typical of bremsstrahlung theories but not transport theories; and (iii) a correction due to ion screening. Radiation-hydrodynamic simulations of inertial confinement fusion implosions have to date used a Coulomb logarithm from the transport literature and no screening correction. We anticipate that updating the model for collisional absorption will substantially revise our understanding of laser-target coupling for such implosions.
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Affiliation(s)
- D Turnbull
- University of Rochester Laboratory for Laser Energetics, Rochester 14623, New York, USA
| | - J Katz
- University of Rochester Laboratory for Laser Energetics, Rochester 14623, New York, USA
| | - M Sherlock
- Lawrence Livermore National Laboratory, Livermore 94550, California, USA
| | - L Divol
- Lawrence Livermore National Laboratory, Livermore 94550, California, USA
| | - N R Shaffer
- University of Rochester Laboratory for Laser Energetics, Rochester 14623, New York, USA
| | - D J Strozzi
- Lawrence Livermore National Laboratory, Livermore 94550, California, USA
| | - A Colaïtis
- Centre Lasers Intenses et Applications, Talence 33400, France
| | - D H Edgell
- University of Rochester Laboratory for Laser Energetics, Rochester 14623, New York, USA
| | - R K Follett
- University of Rochester Laboratory for Laser Energetics, Rochester 14623, New York, USA
| | - K R McMillen
- University of Rochester Laboratory for Laser Energetics, Rochester 14623, New York, USA
| | - P Michel
- Lawrence Livermore National Laboratory, Livermore 94550, California, USA
| | - A L Milder
- University of Alberta, Edmonton, Alberta T6G 2R3, Canada
| | - D H Froula
- University of Rochester Laboratory for Laser Energetics, Rochester 14623, New York, USA
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