May 2007 Work supported by the U.S. Department of Energy under grants DE-FG52-03NA00064, DE-FG52-07NA28058 and other grants and contracts Experiments With

May 2007

Work supported by the U.S. Department of Energy under grants DE-FG52-03NA00064, DE-FG52-07NA28058 and other grants and contracts

Experiments With Astrophysical Applications Experiments With Astrophysical Applications

R. Paul Drake R. Paul Drake University of MichiganUniversity of Michigan

2007 January NNSA Page 2

One way to accomplish shock acceleration

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0 0.001 0.002 0.003 0.004 0.005

β

MA

D/rLi

T/B2

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MA

D/rLi

Plot is for achievable nD2 = 1.4 x 1018 cm-1 Parameters will increase with future, larger nD2

Magnetic Coils (Partial)

MagneticField LinePreformedPlasmaAccelerated Ion Collector/Diagnostic

LaserBeamTarget

From R.P. Drake, Physics of Plasmas, Nov. (2000)


Why HED Lab Astro is important to NNSA

• Providing trained young people – The scientific population at the NNSA labs is aging rapidly – Over the next few years the National Ignition Facility will need a new

generation – I could have easily placed 5 new Ph.D.s this past year

• Advancing NNSA-relevant fundamental science – Most work in the labs is programmatic – Universities have a role to play in doing detailed, systematic,

fundamental work

• Establishing a national community and national advocacy


Current projects

• Supernova-relevant hydrodynamics – Blast-wave driven instabilities – On Omega (Carolyn Kuranz in NLUF talks) – On NIF

• Kelvin Helmholtz – Relevant to astrophysics and ICF – On NIKE (Eric Harding at HESDUP session)

• Radiative shocks – Interesting objects ! – Astrophysically relevant– On Omega – On LIL collaborating with team led by Claire

Michaut

• X-ray diagnostics


Most of our current work uses Omega

One of our shots at the Omega laserCollaborators: LLNL – Remington, Robey, Miles, Edwards, Hansen, Froula, others LLE – Knauer, Boehly Arizona – ArnettChicago – PlewaStony Brook – Glimm, Zhang, SwestyNRL – Aglitskiy, WeaverFrance – Bouquet, Koenig, Busquet


Here is what such lasers do to a material

• The laser is absorbed at less than 1% of solid density

From Drake, High-Energy-Density Physics, Springer (2006)

Rad xport, high-v plas Hydro, rad hydro


Shock waves establish the regime of an experiment


Supernova 1987A motivates scaled hydrodynamic instability experiments

• SN 1987A– A core-collapse supernova – Early high-Z x-ray lines with large

Doppler shifts– Early glow from radioactive heating– The issue is the post-core-collapse

explosive behavior

• In 20 years of simulations– Only one (Kifonidis, 2006) makes

fast enough high-Z material – 3D simulations coupling all the

interfaces where initial conditions matter are not feasible

– NIF experiments can do this– Omega experiments address a

single interface

SN1987A, WFPC2, Hubble

Kifonidis, 2003


Here is a typical target for our supernova hydrodynamics experiments

• Precision structure inside a shock tube

• Hydrodynamics:

– L >> mfp; Re > 105;

– small heat conduction & radiation

Experiment design: Carolyn Kuranz


We build precise, innovative targets

Acrylic cone

Gold cone

Laser-driven surface

Side view

1 m

m

Targets: Mike Grosskopf, Donna Marion, Robb Gillespie, UROP team


We obtain data from two orthogonal directions

Mid-1990’sdata

Dec. 06 data at 21 ns

Data and analysis: Carolyn Kuranz


We are now observing the role of complex initial conditions in spike penetration

Interferogram of complex surface on component provided by GA (analysis: Kai Ravariere)

Preliminary data on mix layer thickness

Data and analysis: Carolyn Kuranz


We collaborate with simulation groups to evaluate our results and validate codes

• Work with the FLASH Center (Chicago), to include 3D adaptive modeling, has now begun.

3D FLASH simulations of recent experiments (density display)

Two-mode system.

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

13.5 ns

7.5 ns

19.5 ns

Single eggcrate mode.


We lead a team to prepare for HED hydrodynamics beyond simulation on NIF

• The unresolved issue in exploding stars– The 3D behavior of a diverging explosion – With multiple, structured interfaces

• This problem cannot be fully simulated with computers – Too big, too complex, high Reynolds number

• NIF can do a very relevant experiment– Also can do transition to turbulence

• Preliminary design-related simulations

• At Michigan and LLNL – (Grosskopf) (Miles)

• Builds on experiments at Omega





National Ignition Facility


We create and study driven radiative shocks

10 drive beamsStrike Be disk

Xe filled tube

• Laser beams launch Be piston into Xe or Ar gas at > 100 km/s

• Piston drives a planar shock

• Radiography detects dense xenon

• Gold grid provides spatial fiducial

• Parameters– 1015 W/cm2 – 0.35 µm light– 1 ns pulse – 600 µm tube dia.

Grid

Target: Mike Grosskopf, Donna Marion, Mark Taylor


We have radiographic images of these radiative shocks

• Average velocity 140 km/sec from t = 0 to 14.6 ns from laser firing

• Two Phys. Plasmas papers

• Exploration of structure will be a next theme

gold grid63 µm

Shot 39927

shock

target wall Data and analysis: Amy Reighard


Advanced diagnostics will measure much more

• Thomson scattering

• Collaboration with Dustin Froula and Siegfreid Glenzer of LLNL

Target: Trisha Donajkowski, Mike Grosskopf, Donna Marion

Design: Amy Reighard

Data and analysis: Amy Reighard With Dustin Froula

Target

Data

•Fitting to data gives –110 km/s fluid velocity

–ZTe = 12 x 300 eV

–Te ≤ Ti ≤ 500 eV

Paper in prep. for Phys. Rev. Lett.


We collaborate very extensively

One of our shots at the Omega laserCollaborators: LLNL – Remington, Robey, Miles, Edwards, Hansen, Froula, others LLE/Rochester – Knauer, Boehly, Frank Arizona – ArnettChicago – Plewa, Hearn, MeakinStony Brook – Glimm, Zhang, SwestyNRL – Aglitskiy, WeaverFrance – Bouquet, Koenig, Michaut, BusquetRochester – Frank Texas – Ditmire


Some highlights of the past year

• Target innovations enabled completion of data set on Rayleigh-Taylor spike penetration

• Moving toward advanced diagnostics of radiative shocks

• Amy Reighard defended her Ph.D.

• Published the first graduate text in High Energy Density Physics

Documents

May 2007 Work supported by the U.S. Department of Energy under grants DE-FG52-03NA00064, DE-FG52-07NA28058 and other grants and contracts Experiments With