Energy absorption and coupling to electrons in the transition from surface- to volume-dominant intense laser-plasma interaction regimes
Williamson, S D R and Gray, R J and King, M and Wilson, R and Dance, R J and Armstrong, C and Rusby, D R and Brabetz, C and Wagner, F and Zielbauer, B and Bagnoud, V and Neely, D and McKenna, P (2020) Energy absorption and coupling to electrons in the transition from surface- to volume-dominant intense laser-plasma interaction regimes. New Journal of Physics, 22 (5). 053044. ISSN 1367-2630 (https://doi.org/10.1088/1367-2630/ab86df)
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Abstract
The coupling of laser energy to electrons is fundamental to almost all topics in intense laser-plasma interactions, including laser-driven particle and radiation generation, relativistic optics, inertial confinement fusion and laboratory astrophysics. We report measurements of total energy absorption in foil targets ranging in thickness from 20 μm, for which the target remains opaque and surface interactions dominate, to 40 nm, for which expansion enables relativistic-induced transparency and volumetric interactions. We measure a total peak absorption of ∼80% at an optimum thickness of ∼380 nm. For thinner targets, for which some degree of transparency occurs, although the total absorption decreases, the number of energetic electrons escaping the target increases. 2D particle-in-cell simulations indicate that this results from direct laser acceleration of electrons as the intense laser pulse propagates within the target volume. The results point to a trade-off between total energy coupling to electrons and efficient acceleration to higher energies.
ORCID iDs
Williamson, S D R ORCID: https://orcid.org/0000-0002-8457-4858, Gray, R J ORCID: https://orcid.org/0000-0003-0610-9595, King, M ORCID: https://orcid.org/0000-0003-3370-6141, Wilson, R, Dance, R J ORCID: https://orcid.org/0000-0001-8252-5342, Armstrong, C ORCID: https://orcid.org/0000-0003-2083-8487, Rusby, D R, Brabetz, C, Wagner, F, Zielbauer, B, Bagnoud, V, Neely, D and McKenna, P ORCID: https://orcid.org/0000-0001-8061-7091;-
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Item type: Article ID code: 71978 Dates: DateEvent27 May 2020Published6 April 2020Published Online6 April 2020AcceptedSubjects: Science > Physics Department: Faculty of Science > Physics
Strategic Research Themes > Measurement Science and Enabling TechnologiesDepositing user: Pure Administrator Date deposited: 06 Apr 2020 14:19 Last modified: 22 Dec 2024 01:24 URI: https://strathprints.strath.ac.uk/id/eprint/71978