Speaker
Description
The pursuit of controlled energy gain by nuclear fusion took a huge leap forwards with the 2022 demonstration of multi-megajoule energy gain from deuterium-tritium implosions at the National Ignition Facility. Attention has now turned to applying these breakthroughs to realize commercially-viable energy production, in particular through the IFE-STAR and FIRE programs from the US Department of Energy.
As part of this decadal effort, the High Energy Density Science (HEDS) division at SLAC is applying its expertise in using pulses from X-ray Free Electron Lasers to study extreme states of matter. These deliver femtosecond pulses with tunable wavelength, which we have used to probe bulk properties of matter and in order to observe phase transitions, ultrafast dynamics and temperature evolution with greater fidelity than can be delivered by any other approach.
A leading design for delivering fusion targets at Hz-level repetition rates uses polymer foam capsules wetted with liquid nuclear fuels. A new program at SLAC will study these targets in high precision experiments with powerful X-ray sources to provide the required equation of state (EoS) data for validation of hydrodynamic simulations.
This talk will cover some of the ways that our existing experiments have begun answering questions about fusions targets and drivers, and what new diagnostics and analysis techniques will still need to be developed. Our recent studies have developed sub-micron resolution X-ray imaging techniques and measured shock propagation, instability growth, and heating of foam targets. Inelastic X-ray scattering with spectral resolution of ΔE/E = 10-6 can resolve the ion feature and plasmons and measure the physical properties of fusion plasmas. I will show examples that use self-seeded X-rays, stochastic correlation of SASE spikes, and Quantum-entangled X-ray photons to accomplish these goals. These results motivate upgrades to the optical drives lasers at MEC at LCLS, and the proposed IFE end station at European XFEL. These future experimental capabilities will couple XFELs to higher-energy and -power lasers than ever before, accessing the pressure conditions found in fusion capsule implosions.