Proton radiography inversions with source extraction and comparison to mesh methods
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- Princeton University, NJ (United States); Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
- Princeton University, NJ (United States)
- Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
- University of Michigan, Ann Arbor, MI (United States)
- University of Rochester, NY (United States)
- University of California, Los Angeles, CA (United States)
In this article, proton radiography is a central diagnostic technique for measuring electromagnetic (EM) fields in high-energy-density, laser-produced plasmas. In this technique, protons traverse the plasma where they accumulate small EM deflections which lead to variations in the proton fluence pattern on a detector. Path-integrated EM fields can then be extracted from the fluence image through an inversion process. In this work, experiments of laser-driven foils were conducted on the OMEGA laser and magnetic field reconstructions were performed using both “fluence-based” techniques and high-fidelity “mesh-based” methods. We implement nonzero boundary conditions into the inversion and show their importance by comparing against mesh measurements. Good agreement between the methods is found only when nonzero boundary conditions are used. We also introduce an approach to determine the unperturbed proton source profile, which is a required input in fluence reconstruction algorithms. In this approach, a fluence inversion is embedded inside of a mesh region, which provides overconstrained magnetic boundary conditions. A source profile is then iteratively optimized to satisfy the boundary information. This method substantially enhances the accuracy in recovering EM fields. Lastly, we propose a scheme to quantify uncertainty in the final inversion that is introduced through errors in the source retrieval.
- Research Organization:
- Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States); University of Rochester, NY (United States)
- Sponsoring Organization:
- National Science Foundation (NSF); USDOE; USDOE National Nuclear Security Administration (NNSA)
- Grant/Contract Number:
- AC02-09CH11466; NA0003868; NA0004034; NA0004144
- OSTI ID:
- 2478140
- Journal Information:
- Physical Review. E, Journal Name: Physical Review. E Journal Issue: 5 Vol. 110; ISSN 2470-0045
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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