Dr. Sarah Nelson

NNSA updates on HEDP (video)

Dr. Slava Lukin

NSF update on HEDP (video)

Dr. Ahmed Diallo

ARPA-E  update on HEDP (video)

Dr. Kramer Akli

FES  update on HEDP (slides)

Dr. John Luginsland

AFOSR  update on HEDP (video)

Dr. Bedros Afeyan

The Green Option for IFE – STUD Pulses, Learned and Adaptive Control of Laser-Plasma Instabilities: Machine Learning Optimum Spike Trains of Uneven Duration and Delay (STUD Pulses) (video)

Polymath Research Inc

Taming Laser-Plasma Instabilities (LPI) is a grand challenge for IFE. Instabilities will not play nice and remain in the linear regime. If they did, control would be trivial. But they won’t. A major reason why they won’t is that laser l beams have speckle patterns which contain high intensity needles interspersed among more abundant low intensity regions. This spread in intensity implied that no matter how things look at the average intensity, the high intensity regions can ignite, self-organize, cross-communicate and otherwise instigate and sustain the brush fire of laser-plasma instability as occurred on the NIF squandering 100’s of kJ and making hohlraum heating histories unknown and unpredictable. Spike trains of Uneven Duration and Delay (STUD) are a way to tame LPI and disallow such plasma self-organization. STUD pulses combat plasma memory buildup. A typical IFE pulse would be composed of 1000-10,000 spikes whose durations, delays, amplitudes and phases must be optimized for best performance. This is a task best handled with machine learning and high rep-rated lasers. In addition, taming LPI allows Green lasers to be considered, ie 2w instead of 3w. This opens up many possibilities such as those pursued by Focused Energy. Xcimer Energy proposed a KrF system which is then amplified and compressed using SRS and SBS. That system with STUD pulses opens a far wider design space for IFE where the amplification and compression of the multi-MJ lasers themselves and the LPI in the target can all be better controlled and tamed.

Conner Galloway

A novel high-energy and low-cost laser architecture to enable inertial fusion energy (video)

Xcimer Energy Corporation

Laser driver cost is a significant obstacle to the development of laser-driven IFE. High laser cost not only leads to unfavorable economics for a power plant, but also pushes IFE design points to low laser energy and high repetition rate. Low laser energy increases target design complexity by requiring high-finesse, high-convergence, low-adiabat implosions. High repetition rate increases chamber design complexity by making target injection and chamber clearing difficult. Xcimer Energy is addressing these challenges with a novel laser architecture that is scalable to tens of megajoules at a cost of tens of dollars per joule. Xcimer’s architecture builds on significant prior work in DOD and DOE programs, and supports a 10 MJ driver, 1 Hz repetition rate IFE design space in which thick liquid walls can be utilized for first wall protection. Xcimer plans to construct a multi-kJ prototype laser facility by late 2024, achieve commercial target gain with a 4+ MJ facility by 2028, and deploy a pilot plant in the 2030s.

Isabella Pagano

(Sponsored by the HEDSA student chapter)

High Resolution Radiography with Self-Modulated and Blowout Regime Laser Wakefield Acceleration generated X-ray sources (video)

University of Texas at Austin

In order to deepen our understanding of High Energy Density Science (HEDS) phenomena, it is necessary to develop diagnostics capable of high spatio-temporal resolution. A broadband X-ray source driven by Self-Modulated laser wakefield acceleration (SM-LWFA) was observed at the Jupiter laser facility. This X-ray source had energies ranging from 10 KeV to > 1 MeV, and we demonstrated potential for applications. There are multiple processes which can use accelerated electrons from SM-LWFA to create X-rays; Betatron, Inverse Compton Scattering, and Bremsstralung. Each mechanism produces an X-ray source with distinct spectral and spatial attributes, which make it crucial to thoroughly characterize both to develop an X-ray source we can apply to HEDS experiments. Our results compare the spectral output and source size for each kind of SM-LWFA driven X-ray radiation. We imaged a modified Air Force resolution target, as well as an inertial confinement fusion hohlraum target, with a tungsten sphere positioned at the center. Analysis of the X-ray radiographs taken utilizing the SM-LWFA X-ray source allowed for determination of the X-ray source size and resolution capability. With the resolution target, we approximated the thin target as a “knife edge,” and examined the resulting near field diffraction pattern, comparing a Fresnel diffraction based calculation of the diffraction pattern to experimental data. For the hohlraum and sphere image, a modified X-ray ray tracing code simulated the line out from an X-ray radiograph. The source size analysis tools developed in this analysis procedure can also be applied to blowout regime LWFA experiments at other facilities such as the Texas Petawatt, producing an additional comparison between the X-ray source characteristics of different regimes of LWFA.

Prof. Jack Hare

Magnetized High-Energy-Density Plasma Experiments at MIT (video)

MIT

Most of the Universe is made from plasma, and much of that plasma is magnetized. Laboratory experiments can complement remote astrophysical observations by generating reproducible and tunable plasma which can be used to study fundamental processes such as magnetic reconnection or magnetized turbulence in detail. In this talk, I will discuss the research carried out by my new group at MIT to study these processes using pulsed-power driven plasmas, including magnetic reconnection experiments on the MAGPIE generator at Imperial College London; radiatively cooled magnetic reconnection on the Z Machine at Sandia National Laboratories; and the new long-pulse PUFFIN generator at MIT.