Z Fundamental Science Program Workshop: Welcome & Introduction

Summary

This presentation serves as the welcome and introduction for the 2020 Z Fundamental Science Program Workshop, presented by Daniel Sinars, Director of the Pulsed Power Sciences Center at Sandia National Laboratories. It highlights the capabilities of the Z Machine in pulsed power and high-energy-density (HED) science, covering research in radiation science, dynamic material properties, and Magneto-Inertial Fusion (MagLIF), as well as future facility proposals and community collaborations.

Slide 1: Title Slide

Z Fundamental Science Program Workshop: Welcome & Introduction Daniel Sinars, Director, Pulsed Power Sciences Center Z Fundamental Science Workshop 8/3/2020 Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc. for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

Slide 2: Welcome

I’d like to extend a warm virtual welcome to all of you! • This year we were faced with choosing the lesser of two evils… o Not having a workshop at all, or… o Having a virtual workshop without the pleasure of face to face interactions, meeting new people, and forging new scientific partnerships. Despite the limitations of this format, we are very much looking forward to sharing our technical progress and the exchange of ideas

Slide 3: Z Fundamental Science Program Priority

The Z Fundamental Science Program is a high priority for our work on the Z facility Z Building

Slide 4: Use-Inspired Research

Majority of Z research is “use-inspired” Conducting open, novel science in the pursuit of applications benefiting the mission of the NNSA Pasteur’s Quadrant: Basic Science and Technological Innovation (Donald E. Stokes)

Relative scientific novelty: LOW to HIGH
Alignment with Mission Needs
Basic Research (~15%)
Use-Inspired Research (~45% - You are here!)
Applied Research (~40%)
Do Not Fund

Slide 5: Z Machine Overview

Z works by compressing energy in space and time to generate high energy density (HED) conditions 80 TW, 26 MA Electrical

Marx Generator (22 MJ Stored)
Pulse Forming Storage Section
Center Section Z today couples several MJ out of 22 MJ stored to the load hardware region at the machine center. Power (TW) vs time (µs) plot showing Marx generators, pulse-forming lines, and insulator stack. Z is an “Engine of Discovery” for stewardship and fundamental HED science

Slide 6: Pressures Generated by Pulsed Power

Pulsed power can generate ~100 Mbar drive pressures, which can be used to obtain even higher pressures such as those in inertial fusion Magnetically Driven Implosion: P = B^2 / (8π) = 105 * (I_MA / 26)^2 / (R_mm)^2 MBar 100 MBar at 26 MA and 1 mm 100 GPa = 1 Mbar ≈ 10^6 atmospheres Pressure equivalent to Energy Density (J/m^3): 1 Mbar = 10^11 J/m^3

Z Storage capacitor: 2e-6 Mbar
TNT: 0.07 Mbar
Internal Energy of H atom: 1 Mbar
Metallic H in Jupiter’s core: 30 Mbar
Z Magnetic Drive Pressure: ~100 Mbar (Push on samples / Compress fuel at high velocity)
Center of Sun: 250,000 Mbar
Burning ICF plasma: 800,000 Mbar

Slide 7: Three Broad Areas of HED Science

Z is a precision tool for high energy density science in three broad areas: (a) On-axis foam, cylindrical wire arrays, magnetic field B (b) Cathode, anode / flyer, drive current I, sample (c) Cathode, anode / sample, uncompressed, stress wave front (d) Metal liner, fusion fuel, axial field, azimuthal field (e) Radiation Science (f) Dynamic Material Properties (g) Inertial Confinement Fusion

Slide 8: Precision Tool Overview (Repeated Focus)

Z is a precision tool for high energy density science in three broad areas: Radiation Science Dynamic Material Properties Inertial Confinement Fusion

Slide 9: X-Ray Creation (Basic)

The Z machine uses 26 mega-amperes of current to create >1 mega-joule of x rays Basic ZR > 2011 parameters:

Marx Energy: 20.3 MJ
Ipeak: 25.8 MA (1.5%)
Peak Power: 220 TW (10%)
Radiated Energy: 1.6 MJ (7%) Sanford et al., PoP (2002); Bailey et al., PoP (2006); Slutz et al., PoP (2006); Rochau et al., PPCF (2007); Rochau et al., PoP (2014).

Slide 10: Radiation-Driven Basic Science Experiments

We collaborate with several institutions to do multiple radiation-driven basic science experiments on a single Z shot Basic

Stellar opacity: Question: Why can’t we predict the location of the convection zone boundary in the Sun? Achieved Conditions: Te ~ 200 eV, ne ~ 10^23 cm^-3
Accretion disk: Question: How does ionization and line formation occur in accreting objects? Achieved Conditions: Te ~ 20 eV, ne ~ 10^18 cm^-3
White dwarf: Question: Why doesn’t spectral fitting provide the correct properties for White Dwarfs? Achieved Conditions: Te ~ 1 eV, ne ~ 10^17 cm^-3 Partners: LLNL, LANL, University of Texas, Ohio State, West Virginia U., U. Nevada-Reno, CEA Sanford et al., PoP (2002); Bailey et al., PoP (2006); Slutz et al., PoP (2006); Rochau et al., PPCF (2007); Rochau et al., PoP (2014).

Slide 11: Hostile Environments Effects (Applied)

A major mission focus for Sandia is assessing the effects of hostile environments on nuclear weapons systems Applied

Electromagnetic Radiation
Air Blast
Cold X-Rays (Surface effects)
Warm X-Rays (Shallow penetration)
Hot X-Rays (Deep penetration)
Gamma Rays (Highest photon energy)
Thermal Neutrons (Free neutron with a kinetic energy of 0.025 eV)

Slide 12: High-Energy X-Ray Yields (Applied)

Sandia and Lawrence Livermore National Laboratories are collaborating to produce record levels of >10 keV X-rays using a variety of Z-pinch sources* Applied New records on a 21-year-old facility! Z and NIF are developing advanced x-ray sources that provide unprecedented >10 keV yields

D.J. Ampleford et al., Phys. Plasmas 21, 056708 (2014).

Slide 13: Precision Tool Overview - Dynamic Materials

Z is a precision tool for high energy density science in three broad areas: Radiation Science Dynamic Material Properties Inertial Confinement Fusion

Slide 14: Dynamic Materials Experiments (Basic and Use-Inspired)

We collaborate with several institutions to do a large number of basic and use-inspired dynamic materials experiments every year

Basic: Question: Would an iron meteor plow into a planet as a bullet, splatter as a drop of rain, or vaporize into a cloud and make iron rain? Achieved Conditions: One of the first determinations of the thermal state of an opaque material on the Hugoniot Partners: Harvard, UC Davis, LLNL
Use-Inspired: Question: How compressible is deuterium under high-pressure conditions? (Affects how easy it is to achieve ignition in the laboratory and planetary physics). Achieved Conditions: Unprecedented precision enabled discrimination between subtle differences in theoretical predictions Techniques: Co-Axial Flyer, Stripline Ramp

Slide 15: Mission-Driven Dynamic Materials Research (Applied)

Sandia applies techniques and diagnostics matured on our use-inspired platforms to directly address mission needs in more challenging experiments Applied Z is a unique platform for dynamic materials research: • Large samples, high pressures, and relevant loading paths • Containment capability allows us to field a wide range of hazardous materials without relying on surrogacy

Compared response of 5- and 52-year-old Pu samples to improve pit aging analysis for certification models
Conducted high-pressure uranium experiments on Z to benchmark LANL and LLNL EOS models
New capabilities are being developed over the next several years to extend our impact for mission work Partners: LANL, LLNL

Slide 16: Precision Tool Overview - ICF

Z is a precision tool for high energy density science in three broad areas: Radiation Science Dynamic Material Properties Inertial Confinement Fusion

Slide 17: MagLIF Concept (Use-Inspired)

MagLIF is a Magneto-Inertial Fusion (MIF) concept Use-Inspired Relies on three components to produce fusion conditions at stagnation:

Magnetization: Suppress radial thermal conduction losses; Enable slow implosion with thick target walls
Preheat: Ionize fuel to lock in B-field; Increase adiabat to limit required convergence
Implosion: PdV work to heat fuel; Flux compression to amplify B-field = Stagnation: Several keV temperatures; Several kT B-field to trap charged fusion products S.A. Slutz et al., Phys. Plasmas (2010); A.B. Sefkow et al., Phys. Plasmas (2014); S.A. Slutz et al., Phys. Plasmas (2018).

Slide 18: MagLIF Scaling

We will continue to test MagLIF scaling through further increases in magnetization, preheat, and drive current; 10s of kJ DT-equivalent yield possible in next 2 years Use-Inspired We are working to demonstrate 20-25 T, 2-4 kJ, 20-21 MA in the next 2 years S. A. Slutz, et al., Phys. Plasmas (2018).

Slide 19: High Energy Density Science Applications of Fusion (Applied)

Fusion drives exciting fundamental and use-inspired science! it is also intended as an enabling tool for stockpile stewardship applications Applied Yield vs High Energy Density Science Applications:

~0.01 MJ: Interplay of thermonuclear fusion burn and mix; Nuclear physics data (reaction-in-flight, fission, and radiochemistry)
>0.1 MJ: Transport of charged particles in plasmas; Threshold for fusion-fission physics
~few MJ: Threshold for enabling complex mix physics studies; Robust radiation and charged particle transport; Robust fusion-fission experiments
20-30 MJ: Higher fidelity versions of the above experiments are possible; Neutron sources for outputs and environmental studies
>500 MJ: Use of fusion targets to drive complex experiments; Use of fusion targets for material properties (EOS, opacity) research; Combined neutron and x-ray environments for outputs and effects studies Excerpt from NNSA 2018 ICF Framework Document

Slide 20: Future High Yield Fusion Facilities

Future high yield fusion facilities would create hot plasmas that would provide even more powerful sources of 10-100 keV X-rays Basic / Use-Inspired / Applied Such a Z-pinch driver would also be capable of powerful radiation-only x-ray sources, and high-pressure dynamic materials experiments.

Slide 21: Next Generation Pulsed Power Facility Proposal

Sandia has proposed a next generation pulsed power facility to the NNSA • World’s most powerful warm x-ray and fast fusion neutron source (hostile nuclear survivability) • Enabling capability for high energy density physics (nuclear explosive package certification) • It would attract and test tomorrow’s stewards of pulsed power research • It would provide a venue for scientific and technical innovation for national security Proposed project start date ~2025 Proposed project completion date ~2032 Z will celebrate ~35 years of z-pinch physics in 2030, with some parts of infrastructure ~45 years old. Sandia is evaluating pulsed power architectures: • ~3x diameter of Z today • Delivers 800-1000 TW of electrical energy • Couples ~10 MJ to fusion targets • Requires new operations concepts to reduce manual labor and potential worker hazards

Slide 22: Growing Community of Practice (ZNetUS)

Sandia is trying to support a growing community of practice in pulsed power research on Z and smaller-scale facilities Z Fundamental Science Program:

Earth and super earths: Properties of minerals and metals
Jovian Planets: Water and hydrogen
Stellar physics: Fe opacity and H spectra
Photo-ionized plasmas: Range of ionization param. ξ URL: https://www.sandia.gov/Pulsed-Power/workshop/2020.html

ZNetUS Community: • Intended to build upon success of the LaserNetUS consortium • 1st workshop held January 6-8, 2020 at La Jolla Shores Hotel • Hosted by Center for Energy Research at UCSD (Prof. Farhat Beg) • Executive Committee and Charter formed • Topics include: Pulsed power technology, Magneto-inertial fusion, Astrophysical plasmas and planetary science, MHD and hybrid code development, Magnetized HED URL: https://cer.ucsd.edu/_news-events-articles/2020/ZNetUS_Workshop_2020.html

Slide 23: Operations During the Pandemic

Sandia is continuing to operate Z during the pandemic § As a national security laboratory, Sandia has maintained continuous operations this year, including Z operations. § >50% of our staff are teleworking, including most of the scientists § We have implemented a number of processes to protect our on-site workforce § Z was shut down for 2 weeks in July due to a positive case in the operations workforce, but resumed shot operations on Friday, July 31. § Travel to Sandia requires prior approval, particularly if we wish to avoid a two-week quarantine prior to stepping foot on site. § Travel by Sandia staff requires prior approval to avoid two-week quarantines upon returning to New Mexico, and is discouraged.

Slide 24: Conclusion & Virtual Tour

Questions? § For a virtual tour of Z, see Z Machine: The People https://www.youtube.com/watch?v=gDLGjQVO2tY