Silvia Pandolfi, SLAC
Abstract:
Decades of research have been devoted to the realization of inertial confinement fusion (ICF) [1]. However, hydrodynamic instabilities seeded by mesoscale imperfections, such as micro-voids, currently prevent achieving fusion ignition in the laboratory [2,3]. It is thus crucial to understand how voids dictate the performances of ICF ablators under extreme conditions and to visualize the evolution of these hydrodynamic instabilities. Here, we demonstrate a novel experimental platform for ultra-fast imaging of
materials under shock compression at the Matter in Extreme Conditions (MEC) instrument at the LCLS xray free electron laser (XFEL).
The unique spatial coherence and ultra-fast pulses of the XFEL probe at LCLS enable x-ray phase-contrast imaging (XPCI) with the high spatial (~400 nm) and temporal (~10s fs) resolution required to visualize the sample’s response to laser-driven shock-compression. Our first experiment, performed at 8 keV, demonstrated the combined use of the LCLS four-pulse train and an ultrafast multi-frame detector to collect time-resolved images from a single sample [4-5]. More recently, experiments conducted at 18 keV photon energy have provided high-resolution, time resolved XPCI data that show a remarkable agreement with
hydrodynamic simulations. Using a new model-based image reconstruction method, successful phase retrieval has enabled the recovery of areal density from static single-pulse images. Applied to driven images, this method will enable us to provide the first quantitative information on 2D spatially-resolved density evolution in of void implosions in ICF ablators materials. Our results will inform material models and radiation hydrocodes, providing crucial benchmarks for materials optimization.
[1] J. H. Nuckolls LLNL, Early Steps toward Inertial Fusion Energy (IFE) (1952 to 1962) (1998).
[2] V. A. Smalyuk et al., High Energ Dens Phys 36, 100820 (2020).
[3] A. L. Kritcher et al., Phys Plasmas 28, 072706 (2021).
[4] P. A. Hart et al., 11038, 110380Q (2019).
[5] D. Hodge et al., SPIE Proceedings 1183908 (2021).
Poster Session Link: https://gather.town/invite?token=0pEoq7VP
If you have any questions for the presenter, please contact them via email: silviap@stanford.edu