Measurements of low-mode asymmetries in the areal density of laser-direct-drive deuterium-tritium cryogenic implosions on OMEGA using neutron spectroscopy
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Areal density is one of the key parameters that determines the confinement time in inertial confinement fusion experiments, and low-mode asymmetries in the compressed fuel are detrimental to the implosion performance. The energy spectra from the scattering of the primary deuterium–tritium (DT) neutrons off the compressed cold fuel assembly are used to investigate low-mode nonuniformities in direct-drive cryogenic DT implosions at the Omega Laser Facility. For spherically symmetric implosions, the shape of the energy spectrum is primarily determined by the elastic and inelastic scattering cross sections for both neutron-deuterium and neutron-tritium kinematic interactions. Two highly collimated lines of sight, which are positioned at nearly orthogonal locations around the OMEGA target chamber, record the neutron time-of-flight signal in the current mode. An evolutionary algorithm is being used to extract a model-independent energy spectrum of the scattered neutrons from the experimental neutron time-of-flight data and is used to infer the modal spatial variations (l = 1) in the areal density. Experimental observations of the low-mode variations of the cold-fuel assembly (ρL0 + ρL1) show good agreement with a recently developed model, indicating a departure from the spherical symmetry of the compressed DT fuel assembly. Another key signature that has been observed in the presence of a low-mode variation is the broadening of the kinematic end-point due to the anisotropy of the dense fuel conditions.
Date Issued
2022-10-05
Date Acceptance
2022-08-17
Citation
Review of Scientific Instruments, 2022, 93 (10), pp.1-9
ISSN
0034-6748
Publisher
American Institute of Physics
Start Page
1
End Page
9
Journal / Book Title
Review of Scientific Instruments
Volume
93
Issue
10
Copyright Statement
© 2022 Author(s).
Sponsor
U.S Department of Energy
Identifier
https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000869126900006&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Grant Number
SUB00000024/GR530167
Subjects
Science & Technology
Technology
Physical Sciences
Instruments & Instrumentation
Physics, Applied
Physics
Publication Status
Published
Article Number
ARTN 103505
Date Publish Online
2022-10-05