Title: Diagnosing magnetic fields in cylindrical implosions with oblique proton radiography

Abstract

Two experiments at the OMEGA Laser System used oblique proton radiography to measure magnetic fields in cylindrical implosions with and without an applied axial magnetic field. Although the goal of both experiments was to measure the magnitude of the compressed axial magnetic field in the core of the implosion, this field was obfuscated by two features in the coronal plasma produced by the compression beams: an azimuthal self-generated magnetic field and small length scale, high-amplitude structures attributed to collisionless effects. In order to understand these features, synthetic radiographs are generated using fields produced by 3D HYDRA simulations. These synthetic radiographs reproduce the features of the experimental radiographs with the exception of the small-scale structures. A direct inversion algorithm is successfully applied to a synthetic radiograph but is only partially able to invert the experimental radiographs in part because some protons are blocked by the field coils. The origins of the radiograph features and their dependence on various experimental parameters are explored. Furthermore, the results of this analysis should inform future measurements of compressed axial magnetic fields in cylindrical implosions.

Authors:

Heuer, P. V.  ^[1];

• Search DOE PAGES for author "Heuer, P. V."
• Search DOE PAGES for ORCID "0000-0001-5050-6606"

Leal, L. S.  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-4602-2999"

Davies, J. R.  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-8233-8272"

Hansen, E. C.  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-8565-9602"

Barnak, D. H.  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-4646-7517"

Peebles, J. L.  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-6488-3277"

García-Rubio, F.  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-7168-3190"

Pollock, B.  ^[2];

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• Search DOE PAGES for ORCID "0000-0003-4534-0941"

Moody, J.  ^[2];

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• Search DOE PAGES for ORCID "0000-0003-3132-0122"

Birkel, A.  ^[3];

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• Search DOE PAGES for ORCID "0000-0001-7638-0706"

Seguin, F. H. ^[3]

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+ Show Author Affiliations

1. University of Rochester, NY (United States)
2. Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
3. Massachusetts Institute of Technology (MIT), Cambridge, MA (United States)

Publication Date:

Mon Jul 18 00:00:00 EDT 2022

Research Org.:

Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA); USDOE Advanced Research Projects Agency - Energy (ARPA-E)

OSTI Identifier:

1885760

Alternate Identifier(s):

OSTI ID: 1876467; OSTI ID: 1973192

Report Number(s):

LLNL-JRNL-846892
Journal ID: ISSN 1070-664X; 2022-113; 1735; 2697; TRN: US2309648

Grant/Contract Number:  

SC0020431; NA0003856; AR0000568; AC52-07NA27344

Resource Type:

Accepted Manuscript

Journal Name:

Physics of Plasmas

Additional Journal Information:

Journal Volume: 29; Journal Issue: 7; Journal ID: ISSN 1070-664X

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

70 PLASMA PHYSICS AND FUSION TECHNOLOGY; magnetic fields; magnetic equipment; laser ablation; radiography; magnetohydrodynamics; electromagnetism