Center for Laboratory Astrophysics: Structure Formation and Energy Transport After the Dark Ages
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Center for Laboratory Astrophysics:
Structure Formation and Energy
Transport After the Dark Ages
PIs: Carolyn C. Kuranz and R Paul Drake
University of Michigan
A report on work funded by the Stockpile Stewardship Academic Alliances and by the
National Laser User Facility through grant numbers DE-FG52-09NA29548 and DE-
FG03–00SF22021
The Center also has or has had support
from LLE, LLNL, DTRA, LANL, NRL, and ASC
The Center Laboratory Astrophysics (CLA) studies high-energy-density phenomena that are relevant to astrophysics • We advance fundamental understanding of HED dynamics relevant to astrophysics – Radiation hydrodynamics – Complex HED hydrodynamics – Magnetized flowing plasma • While advancing the required infrastructure – Computer simulation X-ray radiography of Kelvin- – Target fabrication Helmholtz instability from the – HEDP diagnostics Omega EP facility • The ultimate goal of these activities is to train junior scientists
CLA relies on senior faculty and
scientists with a breadth of experience
• Faculty:
– Kuranz, Drake
• Staff:
– Trantham, Klein, Gillespie
Kuranz Drake Klei Trantham
• Additional HEDP Faculty at UM: n
– Johnsen (ME), McBride (NERS), Willingale (EECS), Thomas
(NERS), Krushelnick (NERS)
The CLA team is oriented
toward training students
• Most of our students come through the
UM Applied Physics Program
– Outstanding applicants; highly competitive
– Diverse program – 30% women, 30% URM
– Imes-Moore Fellowship (1st generation
citizen, 1st generation college, financial
hardship)
• We graduate about 1 – 2 students/year
• We have over 100 publications since 2009
– About 12/year
The CLA team is oriented
toward training students
• Post Docs: Rachel Young Undergraduates
• Current Grad Students Spencer Paulissen (SULI)
Alexander Rasmus (LANL, Omega) Skylar Hau (SULI)
Pat Belancourt (Omega) Connor Todd
Robert Vandervort (Omega) Liam Alexis (LANL)
Laura Elgin (Omega) Kayce Duggan
Joseph Levesque (Omega) Karl Kirchner
Heath LeFevre (Omega, NIF) Recent Graduates
Adrianna Angulo (LLNL, Omega, NIF) Michael MacDonald (2016, UCB, LLNL)
Shane Coffing (LANL) Jeff Fein (2017, SNL)
Rachel Young (2017, UM)
Raul Melean (MAIZE)
Willow Wan (2017, LANL)
Alexander Rasmus (next week!, LANL)
Student spotlight: Dr. Willow Wan
• US citizen
• BS 2010, Physics and English, Montclair
State University
• PhD 2017, CLASP
– “Supersonic, single-mode and dual-mode
Kelvin-Helmholtz instability experiments
driven by a laser-produced shockwave”
– Publications: Phys. Rev. Let., Phys. Of
Plasmas, High Energy Density Phys.
• Multiple “Best Poster” Awards
• National Ignition Facility and Photon
Science Award
• Currently a Postdoctoral Fellow at LANL
PRL, 2015
We value our scientific collaborators*
Negev/Israel – Malamud, Elbaz, Shimony
Rice – Hartigan
LLE/Rochester –Theobald, Frank, Blackman
LLNL – Huntington, Park, Moody, Remington,
Doeppner, MacDonald
LANL – Flippo, Li, Liao, Kline, Keiter,
Montgomery, Di Stefano, Johns, Urbatsch
SNL – Knapp, Doss, Hansen, Loisel
Center for Laboratory Astrophysics,
France – Koenig, Bouquet, Michaut, Falize, Los Alamos National Laboratory,
Casner, Fuchs Nuclear Research Center– Negev
HED Hydrodynamic collaboration
Florida State – Plewa
University of Nevada – Mancini
MIT - Li
*a partial list
We have been fabricating targets for
our experiments since 2004
Components for
photoionization
front gas target
Some components are
fabricated at General Atomics
Sallee Klein and students gas filling Omega-EP Kelvin Helmholtz
targets at LLE target, Wan, Malamud
We modeled our experiments in CRASH, a
radiation hydrodynamic code
3D Nozzle to Ellipse @ 13 ns
• 1D, 2D or 3D
• Dynamic adaptive mesh refinement
• Level set interfaces
• Self-consistent EOS and opacities Material & AMR
• Multigroup-diffusion radiation
transport
• Electron physics and flux-limited Log Density
electron heat conduction
• Laser package
– 3D ray tracing for 2D or 3D runs Log Electron Temperature
Log Ion Temperature
CRASH code: Van der Holst et al, Ap.J.S. 2011
7th High Energy Density Physics Summer School, June 11 – 22, 2018 • 2 week lecture course on HEDP fundamentals • High-Energy-Density Physics: Foundations of Inertial Fusion and Experimental Astrophysics • 35 students/postdocs from university, national labs, and industry Lectures by Kuranz, Drake, Thomas, • Simulation tutorials (Hyades Willingale, McBride, Johnsen, Young, and kinetic models), and Trantham laboratory tours (MAIZE, CUOS, Target Fab Lab) University of California is hosting a summer school this year!
The early history of the universe
informs our present research
Star formation in clouds
Era of reionization
Fueling early galaxies
Adapted from Brant E. Robertson, Richard S. Ellis, James S. Dunlop, Ross J. McLure, and
Daniel P. Stark, Early star-forming galaxies and the reionization of the Universe, Nature 468,
49 (2010).Streams of infalling hot matter from the
cosmic web are thought to have fueled
early galaxies
• Filaments may be
Kelvin-Helmholtz
unstable
• Galactic simulations
are not well resolved
• We designed a well
scaled experiment to
Galaxy bimodality due to cold flows and study this
shock heating, Dekel and Birnboim, Mon.
Not. R. Astron. Soc. 368, 2–20 (2006)We identified key experimental and astrophysical parameters Graduate Student: Shane Coffing
We have designed a well-scaled experiment Graduate Student: Shane Coffing
CRASH aided in the design of this experiment Graduate Student: Shane Coffing
The target has a micro-machined
pattern to seed the KH instability
20 ps
Cu backlighter
laser
Imaging
x-rays
0.2 mm
Physics
Package
30 ns Laser
laser
Machined rod
Image Plate
Experiment
0.2 mm
Crystal
Diagnostic
Graduate Student: Adrianna AnguloEarly experiments on this system
have produced promising results
1.2 mm
W
We are quantifying the mass transport in the
experiment and astrophysical case
Graduate Student: Adrianna AnguloOur goal is to probe star formation at moderate optical depth Optically thick: Photons absorbed at one cloud edge drives asymmetric shock Optically thin: Photons permeate and heat cloud and it explodes
Stars are not predicted to form if the photon
flux is too low or the radiation mean free
path is larger than the cloud size
We probe this boundary
Adapted from Bertoldi Astrophys. J. 1989The experiment is in a similar regime as a typical, radiation-driven, astrophysical implosion Mach v - ratio of the speed of the shock driven into the cloud on axis to the sound speed corresponding to the ionization front produced by the source
CRASH simulations show compression or explosion based on the initial foam density
A range of optical depths is accessible by
changing the sphere diameter and density
First
exptsOptically thick limit provides a starting point to test the platform Graduate Student: Robert Vandervort
Backlit-pinhole radiography shows an asymmetrically-compressed sphere Graduate Student: Robert Vandervort
Soft x-ray radiographs suggest an asymmetric compression Graduate Student: Robert Vandervort
CLA Presentations at SSAP Alex Rasmus Graduate Student/Postdoc Laura Elgin Graduate Student (defending 2019) Heath LeFevre Graduate Student Samuel Pellone Graduate Student Shane Coffing Graduate Student Adrianna Angulo Graduate Student
The Center Laboratory Astrophysics (CLA) studies high-energy-density phenomena that are relevant to astrophysics • We advance fundamental understanding of HED dynamics relevant to astrophysics – Radiation hydrodynamics – Complex HED hydrodynamics – Magnetized flowing plasma • While advancing the required infrastructure – Computer simulation X-ray radiography of Kelvin- – Target fabrication Helmholtz instability from the – HEDP diagnostics Omega EP facility • The ultimate goal of these activities is to train junior scientists
We experiment and collaborate at
many HEDP facilities
Led by CLA: Facility Collaborative Facility
participation
Radiation Hydro Omega/NIF XRTS Omega/NIF
Complex Hydro Omega/NIF LLNL Complex Hydro Omega/NIF
Magnetized Flows Omega/MAIZE LANL Complex Hydro Omega
X-ray Thomson Scatt. NIF Magnetized Flows Omega/JLFRecent Graduates for CLA
• Michael MacDonald (2016, UCB, LLNL)
• Jeff Fein (2017, SNL)
• Rachel Young (2017, UM) Young
• Willow Wan (2017, LANL)
• Alexander Rasmus (next week!, LANL)
Wan
FeinReionization and star formation
both involve phenomena triggered
by x-rays
• Grad student Josh Davis developed the needed x-ray source
– Reionization involves photoionization fronts
– Radiation can disrupt or trigger star formation in clouds
Various gas seals
30The Omega Facility has played a key
role in our providing scientists to US
national-security labs
• Omega is an excellent place to provide
relevant training
• Students can make mistakes while doing projects of interest
• 19 doctoral students from our group have been directly involved at
Omega
• Several others indirectly
• Of the 12 who have graduated, 7 have gone to the NNSA labs
• 3 others are involved with NNSA from universities or GA
LLNL
SNL
UM
ATK LLNL
LANL
SNL LANL
UM
LANL GA
31Photoionization fronts drove
reionization
• Photoionization fronts are dynamic
structures
– Producing ionization, shock waves, and
expansions
– Interactions produced much structure
in the first galaxies
• No experiment has ever met the
requirements to produce one:
– Photoionization >> recombination near
the front
– Photoionization >> electron-impact
ionization at the front
• We are attempting to produce one
– On Omega via theory, atomic physics,
simulations, and experiment design
32that
producing photoionization fronts
• “Zero-D” calculations of population dynamics
might bebyfeasible
– Informed experimental realities and geometry
– Theory (Drake et al, Ap.J.16); Atomic physics (Patterson, in prep)
• Implications
– Need Omega to get strong photoionization over enough volume
– For photoionization to exceed other processes, need gas target
– For achievable experimental volumes, can’t make H work
Photoionization cross
sections for N (solid)
Spectrum for 100 eV
source (dashed)
33One still needs to assess overall
energy balance
•and lateralaccomplish
2D simulations heat this
losses
– Used our CRASH rad-hydro code
– Diffusive heat transport models for radiation (multi-group) and
electrons (single-group)
– These models pull radiation out in front for conditions that will have
strong photoionization
Very small Radiation temperature (solid)
density changes leads electron temperature (dashed)
(Gray et al.,
Astroph. J.
submitted)
34The simulations also help
understand scaling
• Evaluation of whether photoionization is large enough
– Darker colors are good
– Gas pressure (and ionization on small scale) increase up
– Source temperature (and time on small scale) increase to right
(Gray et al.,
Astroph. J.
submitted)
35The first attempt at a
photoionization front experiment
will be later
• Elements this
of the year
experiment
• Lasers strike Au foil; x-rays drive photoionization front
• Trace (~1%) amount of argon dopant in N2 gas
• Lasers strike plastic capsule, generating continuum x-ray source for
absorption spectroscopy (Keiter, HEDP 2016)
• Streaked spectra will observe passing of photoionization front
• The front should propagate kinematically
– Expect
– A diffusive, electron heat front would scale
differently
– Strong success would be producing an extended
region at N 5+
36The study of energy transport effects on the Rayleigh-Taylor instability is relevant to SN1993J a core-collapse, red supergiant
We use to NIF drive a create a high- and low- energy flux in an RT unstable system PI: Hye-Sook Park, Channing Huntington, Carolyn Kuranz
Typical data show qualitative and
quantitative differences between cases
Low energy flux High energy fluxWe must compare the RT growth of each case A(t) is the Atwood number, g(t) is the acceleration and k is the wave number of the initial perturbation
Experimental data and CRASH simulations are in good agreement
We found that high energy fluxes reduce the RT growth • Energy fluxes due to radiative losses and electron heat conduction are large in SN1993J and the NIF experiment • These fluxes should be considered in astrophysical modeling • This work is in press at Nature Communications
We are also exploring magnetized bow shocks • Supersonic plasma outflows interact with astrophysical bodies, forming bow shocks • Around magnetized objects, magnetic pressure alters flow dynamics • A magnetopause forms where
This is relevant to the Earth’s magnetosphere, which has complex dynamics Image credit: SOHO (NASA / ESA)
Proton radiography and imaging
Thomson scattering diagnostics
probe the shock
ITS
6 mmImaging Thomson scattering
measured plasma properties
across a shock front
Shock
• Electron plasma wave scattering
Incoming spectra shown
flow – Estimated errorProton radiography also provides information about the shock
We generated synthetic proton
images using imaging TS data and
imposed field
The field jump at the shock is
primary cause of the dark band(s)
Analysis by Joseph LevesqueWe believe we have reached a
suitable βram regime for early times
This experiment can be
performed on pulsed power
devices (MAIZE)Backup Slides
Using ITS and proton imaging may
allow us to infer magnetic field
properties at the shock
• Generate synthetic proton images
based on imposed magnetic field
using ITS data
• Distance of shock from wire: 1.2
mm
• Estimated Shock depth (into page):
0.8 mm
• Assume no magnetic field behind
shock
Analysis by Joseph LevesqueHigh Energy Density Physics Summer School, June 11 – 22, 2018 Fundamental Equations Equations of State Shocks and Rarefactions Hydrodynamic Instabilities Radiative Transfer Radiation Hydrodynamics Creating HED Conditions Inertial Fusion Experimental Astrophysics Relativistic Systems Magnetohydrodynamics Lectures by Kuranz, Drake, Thomas, Willingale, McBride, Johnsen, Young, and Trantham
Student spotlight: Dr. Willow Wan
• US citizen
• BS 2010, Physics and English, Montclair
State University
• PhD 2017, CLASP
– “Supersonic, single-mode and dual-mode
Kelvin-Helmholtz instability experiments
driven by a laser-produced shockwave”
– Publications: Phys. Rev. Let., Phys. Of
Plasmas, High Energy Density Phys.
• Multiple “Best Poster” Awards
• National Ignition Facility and Photon
Science Award
• Currently a Postdoctoral Fellow at LANL
PRL, 2015 53You can also read
