Kamboj, Oriza, Ghotra, Harjit Singh, Thakur, Vishal et al. (2 more authors) (2021) Optimizing laser focal spot size using self-focusing in a cone-guided fast-ignition ICF target. European Physical Journal Plus. 484. ISSN 2190-5444
Abstract
This paper presents a scheme for strong self-focusing of a laser beam interacting with a cone-guided fast-ignition inertial confinement fusion target using cone pre-plasma filling as an optical medium for reducing the laser beam waist. The objective is to reduce the focal spot size at the interior of the tip of the re-entrant cone to that required for efficient coupling to the dense imploded fuel core. This is challenging to achieve in a large laser system using the standard optical components of a chirped-pulse-amplified (CPA) laser-beam chain where the spot sizes produced are often significantly larger than would be desirable for fast ignition. The approach described also makes use of the presence of pre-plasma in the cone. Such pre-plasma filling is difficult to avoid entirely when illuminating a cone with a high-energy CPA laser system due to the challenges of reducing laser pre-pulse to below the threshold for plasma production. For deriving the differential equation which governs the progress of the laser beam-width with propagation distance, paraxial theory in a WKB approximation has been used. A simulation is performed assuming strong self-focusing in accordance with the laser parameters and plasma density profile chosen.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Physics (York) |
Depositing User: | Pure (York) |
Date Deposited: | 05 May 2021 10:50 |
Last Modified: | 28 Nov 2024 00:33 |
Published Version: | https://doi.org/10.1140/epjp/s13360-021-01488-8 |
Status: | Published |
Refereed: | Yes |
Identification Number: | 10.1140/epjp/s13360-021-01488-8 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:173747 |