Localized mix-induced radiative cooling in a capsule implosion at the National Ignition Facility

B Bachmann; J E Ralph; A B Zylstra; S A MacLaren; T Döppner; D O Gericke; G W Collins; O A Hurricane; T Ma; J R Rygg; H A Scott; S A Yi; P K Patel

doi:10.1103/PhysRevE.101.033205

Localized mix-induced radiative cooling in a capsule implosion at the National Ignition Facility

Phys Rev E. 2020 Mar;101(3-1):033205. doi: 10.1103/PhysRevE.101.033205.

Authors

B Bachmann¹, J E Ralph¹, A B Zylstra^{1

2}, S A MacLaren¹, T Döppner¹, D O Gericke³, G W Collins^{4

5}, O A Hurricane¹, T Ma¹, J R Rygg^{4

5}, H A Scott¹, S A Yi², P K Patel¹

Affiliations

¹ Lawrence Livermore National Laboratory, Livermore, California 94551, USA.
² Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
³ Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom.
⁴ Departments of Mechanical Engineering, Physics and Astronomy, University of Rochester, Rochester, New York 14623, USA.
⁵ Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA.

PMID: 32290020
DOI: 10.1103/PhysRevE.101.033205

Abstract

We present direct measurements of electron temperature variations within an inertially confined deuterium-tritium plasma caused by localized mix of higher-Z materials into the central hot spot. The data are derived from newly developed differentially filtered penumbral imaging of the bremsstrahlung continuum emission. Our analysis reveals distinct localized emitting features in the stagnated hot-spot plasma, and we infer spatial variations in the electron temperature: the mixed region is 660±130eV colder than the surrounding hot-spot plasma at 3.26±0.11keV. Our analysis of the energy flow shows that we measure approximately steady-state conditions where the radiative losses in the mix region are balanced by heat conduction from the surrounding hot deuterium-tritium plasma.