7:00    Dr. Jim Van Dam

DOE Office of Science perspective on HEDP

7:20    Dr. Slava Lukin (on behalf of Dr. Denise Caldwell)

NSF perspective on HEDP

7:40 Ann Satsangi

NNSA perspective on HEDP

8:00    Jessica Pilgram

(Sponsored by the HEDSA student chapter)

High Repetition Rate Investigation of the Biermann Battery Effect Over Large Volumetric Regions

Phoenix Laboratory, UCLA

The Biermann Battery effect is a mechanism of spontaneous magnetic field generation in both astrophysical phenomena and laser produced plasmas (LPPs). This effect is caused by non-parallel temperature and density gradients within a plasma, represented in the magnetohydrodynamic framework by the baroclinic term in the induction equation, c/en_e  ∇ ⃑T_e× ∇ ⃑n_e. In this talk we present a high repetition rate laboratory astrophysics experiment examining the spatial structure and evolution of Biermann generated magnetic fields in LPPs. Our measurements show azimuthally symmetric magnetic fields with peak values of 60 G in our closest measurements, 0.7 cm from the target surface. Optical Thomson scattering measurements give values for the electron temperature and density of the LPP on axis, of T_e=10±2 eV, and n_e=(5.55±1)×10^16  cm^(-3), respectively. The velocity of the LPP's front has been estimated to be 330 km/s by measuring the time and position of the maximum magnetic fields measured. The expansion rate of the magnetic fields, and current density within the system are also mapped and examined.

 8:25    Dr. Derek Schaeffer

Cosmic Shockwaves in the Lab

Princeton University

Magnetized collisionless shocks are ubiquitous in space and astrophysical plasmas, from Earth’s bow shock to extreme environments such as supernova remnants and black hole jets.  The highly non-linear kinetic physics of these phenomena remains poorly understood, including the mechanisms by which particles are shock-accelerated to some of the highest energies observed in the cosmos.  Despite decades of spacecraft and remote sensing observations, as well as numerical simulations, many key questions remain unanswered, such as what mechanisms underlie shock-accelerated particles or how energy is partitioned across a shock.  Advances in high-powered lasers, strong external magnetic fields, and plasma diagnostics have now enabled collisionless shocks to be created and studied in the laboratory, while still retaining key dimensionless parameters similar to space and astrophysical systems.  This talk will overview recent experiments on magnetized collisionless shocks, including the different types of shocks that can be created, how these shocks are created and diagnosed, what we can learn from laboratory shocks, and the future of collisionless shock experiments.

 8:50 Dr. Annie Kritcher

Results from the HYBRID-E DT experiment N210808 with > 1.3 MJ yield

LLNL

The inertial fusion community have been working towards ignition for decades, since the idea of inertial confinement fusion (ICF) was first proposed by Nuckolls, et al., in 1972 [1].  On August 8, 2021, ignition was finally demonstrated in the laboratory on the National Ignition Facility in Northern California.  The experiment, N210808, produced a fusion yield of 1.35 MJ from 1.9 MJ of laser energy and appears to have crossed the tipping-point of thermodynamic instability according to several ignition metrics.  This talk discusses how the Hybrid strategy [2], a strategy for increasing hot-spot energy while maintaining high hot-spot pressures, was implemented to achieve record ICF performance. A key focus of the talk will be how we utilized increased capsule scale and smaller case-to-capsule ratio in the target design, while also controlling symmetry using a data-based understanding of hohlraum physics [3] and cross-beam energy transfer [4] previously demonstrated in low gas-fill hohlraums. This talk will also detail the subtle importance of “coast-time” (the time duration between the stagnation phase of the implosion and peak ablation pressure) in the design of Hybrid-E.  Data and models have shown that low coast-time is essential for high hot-spot stagnation pressure [5] and the physics of why this is the case will also be mentioned.  In particular, we’ll discuss how a small reduction in coast-time and improvements in target quality were sufficient to make rapid progress from a burning plasma [6,7] to ignition, highlighting the threshold nature of ignition.

[1] J. Nuckolls, et al., Nature, 239, (1972)
[2] O.A. Hurricane, et al., PPCF 61, 014033 (2019); Op Cit., Phys. Plasmas, 26, 052704 (2019)
[3] D.A. Callahan, et al., Phys. Plasmas, 056305 (2018)
[4] A.L. Kritcher, et al., Phys. Rev. E, 98, 053206 (2018)
[5] O.A. Hurricane, et al., Phys. Plasmas, 24, 092706 (2017)
[6] A.B. Zylstra, O.A. Hurricane, et al., in preparation (2021)
[7] A.L. Kritcher, C.V. Young, and H.F. Robey, et al., in preparation (2021)

 9:15 Dr. Varchas Gopalaswamy

Advancing OMEGA ICF implosions to hydro-equivalent ignition

LLE

Maximizing the performance of ICF experiments is necessary to achieve high yield thermonuclear ignition, and realize the goal of harnessing nuclear fusion for energy generation. The efficient design of high performance has long been obstructed by the lack of accurate predictive models, due in large part to the complex, nonlinear, multi-scale physics involved in a laser fusion experiment. A method used to design, quantitatively predict, and interpret the results of implosions of cryogenic deuterium–tritium lined spherical targets on the  OMEGA laser system is presented. This method has increased OMEGA yields by an order of magnitude. When scaled to the laser energies of the National Ignition Facility, these targets are predicted to produce a fusion energy output of over a megajoule.