Identification of stimulated Raman side scattering in near-spherical coronal plasmas on OMEGA EP
| Autor: | Steven Hironaka, Janukan Sivajeyan, James Wang, Michael J. Rosenberg, Andrey Solodov, Timothy Filkins, Chengzhuo Xiao, Qing Wang, Wolf Seka, Jason F. Myatt |
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| Rok vydání: | 2023 |
| Předmět: | |
| Zdroj: | Physics of Plasmas. 30:022708 |
| ISSN: | 1089-7674 1070-664X |
| DOI: | 10.1063/5.0134000 |
| Popis: | Recent spherical-target laser–plasma interaction experiments, performed on the OMEGA EP laser, have been analyzed for stimulated Raman scattering (SRS). This has been motivated by results obtained on the National Ignition Facility (NIF) that have demonstrated the importance of SRS, and in particular SRS side scatter, for directly driven inertial confinement fusion (ICF) conditions [Rosenberg et al. Phys. Rev. Lett. 120, 055001 (2018); Michel et al. Phys. Rev. E 99, 033203 (2019)]. The analysis, based on a generalized ray tracing approach, is described and is shown to explain the observed scattered light spectra: it identifies SRS convective scattering, from portions of each incident beam where the scattered electromagnetic wave is generated in the direction parallel to contours of constant density, as the dominant contribution. This result is novel, as SRS is mostly associated with plasmas of higher electron temperature ([Formula: see text] keV) and longer density scale length ([Formula: see text]m) than those considered here ([Formula: see text] keV, [Formula: see text]m) for the relevant overlapped irradiation intensities [Formula: see text] W/cm2. A combination of the high single-beam intensity on OMEGA EP and the side-scattering geometry, that has been identified, is responsible for this result. It is further suggested that the OMEGA EP platform could provide a good surrogate in which to develop SRS mitigation strategies. |
| Databáze: | OpenAIRE |
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