Exploding pusher targets, i.e. gas-filled large aspect-ratio glass or plastic shells, driven by a strong laser- generated shock, are widely used as pulsed sources of neutrons and fast charged particles. Recent experiments on exploding pushers provided evidence for the transition from a purely fluid behavior to a kinetic one [1]. Indeed, fluid models largely overpredict yield and temperature as the Knudsen number Kn (ratio of ion mean-free path to compressed gas radius) is comparable or larger than one. At Kn = 0.3 - 1, fluid codes reasonably estimate integral quantities as yield and neutron-averaged temperatures, but do not reproduce burn radii, burn profiles and DD/DHe3 yield ratio. This motivated a detailed simulation study of intermediate-Kn exploding pushers. We will show how simulation results depend on models for laser- interaction, electron conductivity (flux-limited local vs nonlocal), viscosity (physical vs artificial), and ion mixing. ∗Work partially supported by Sapienza Project C26A15YTMA, Sapienza 2016 (n. 257584), and Eurofusion Project AWP17-ENR- IFE-CEA-01.
Numerical simulation of exploding pusher targets / Atzeni, S.; Rosenberg, M. J.; Gatu Johnson, M.; Petrasso, R. D.. - In: BULLETIN OF THE AMERICAN PHYSICAL SOCIETY. - ISSN 0003-0503. - 62:12(2017), pp. 417-417. (Intervento presentato al convegno 59th Annual Meeting of the Division of Plasma Physics, Americal Physical Society tenutosi a Milwaukee, Wisconsin, USA).
Numerical simulation of exploding pusher targets
S. Atzeni;
2017
Abstract
Exploding pusher targets, i.e. gas-filled large aspect-ratio glass or plastic shells, driven by a strong laser- generated shock, are widely used as pulsed sources of neutrons and fast charged particles. Recent experiments on exploding pushers provided evidence for the transition from a purely fluid behavior to a kinetic one [1]. Indeed, fluid models largely overpredict yield and temperature as the Knudsen number Kn (ratio of ion mean-free path to compressed gas radius) is comparable or larger than one. At Kn = 0.3 - 1, fluid codes reasonably estimate integral quantities as yield and neutron-averaged temperatures, but do not reproduce burn radii, burn profiles and DD/DHe3 yield ratio. This motivated a detailed simulation study of intermediate-Kn exploding pushers. We will show how simulation results depend on models for laser- interaction, electron conductivity (flux-limited local vs nonlocal), viscosity (physical vs artificial), and ion mixing. ∗Work partially supported by Sapienza Project C26A15YTMA, Sapienza 2016 (n. 257584), and Eurofusion Project AWP17-ENR- IFE-CEA-01.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
