Ray ouerbach

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Status of Fast Ignition-High Energy Density
Physics Joe Kilkenny Director Inertial Fusion
Technology General Atomics San Diego, California

October 19, 2003
Fusion Power
Associates
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Ignition and gain curves for multiple target
concepts show the advantages of Fast Ignition
FI at NIF
Intensity 1014 - 1015 w/cm2
Advanced Indirect Drive on NIF
Intensity 1020 w/cm2
Indirect Drive

Fast ignition potentially gives more gain and
lower threshold energy then Hot Spot ICF but
the science and technology are far less developed
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Fast Ignition has attractive features in addition
to high gain at lower total drive energy

• Challenging science and technology
• Compression MIGHT be possible with all Drivers
• ?0.53 ?m , 1.05?m (?)
• Brightness requirements for compression drivers
  are reduced
• Radiation temperatures of 100ev required for
  compression!
• Direct and Indirect target schemes for
  compression
• Innovative target concepts
• one-sided indirect drive
• indirect drive illumination ( PDD) for direct
  drive
• asymmetric compression drive configurations
• Target fabrication tolerances are relaxed

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NIF produces 4 MJ at 1.05 ?m
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Fast Ignition is compatible with all drivers

• Innovative target designs are possible
• BUT
• Ignitor laser energy must be determined!

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NNSA is interested too! The photons, electrons
and ions from PW lasers can be used to heat and
diagnose HEDP plasmas
Multi-kJ PWs are now planned for OMEGA(EP), Z-R,
and NIF
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The Z-Beamlet laser is being upgraded to provide
a high energy PW laser for use on Sandias Z
facility
Z multimegajoule z-pinch facility
The Z-Beamlet laser will provide a 2-4 kJ,
1-10 psec laser 2007
A 50-200 J, 0.5 - 10 psec prototype laser
system will begin operation in 2004.
Z-Beamlet multikilojoule laser facility
Z z-pinch facility
Z-Beamlet and Z-PW laser facility
High energy radiography and fast ignitor
experiments on Z facility
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Resistive inhibition needs testing under ignition
relevant conditions
e
Critical Surface Dense Gold Coronal
Plasma/Gold Compressed Core
Experiments are needed in low resistivity plasmas
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US OFES effort addresses all aspects of FI
US Fusion Energy program OFES

• OFES support is highly leveraged
• Complementary programs
• Internal funds
• Overseas collaborations
• FI Target design efforts at NNSA funded labs
• SNL - Z - PW
• LLE - Omega EP
• LLNL - NIF -HEPW

Fast Ignition Concept Exploration
Ignition target design
Princeton
LLNL
LLE
UN,Reno
GA
SNL
UC Davis
GekkoXII
Vulcan
LULI
OMEGA
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Hydro Modeling agrees very well

• Stagnation time, shape
• Compressed density
• Emission from target
• Model does not include mixing of Au vapor with
  collapsing shell - will measure from excess
  self-emission

Compact mass, 60 mg/cm2 minimal cone vapor
Models may be sufficiently accurately to for
target design extrapolations
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Electron beam is moderately well directed

• Minimum spot size 70 mm, cone angle 40
• Insensitive to pulse energy (to 100 J)

180 mm
Al 20 mm
Cu 20mm
Al thickness micron
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Integral FI experiments at Gekko XII-PW have
catalyzed FI interest worldwide
GEKKO laser 12 green laser beams E 10 kJ, t
1-2 nsec. Uniform irradiation(phase plates) for
high density compression. I 1014 watts/cm2
PW laser 1 beam (400 J) At 1 micron. PW peak
power is utilized for fast heating. I1019
watts/cm2
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Integral experiments at ILE show efficient heating
ILE Osaka
Rqd timing 50ps

• Nine drive beams, 2.5 kJ
• 1/2 PW ignition beam
• Deuterated plastic target

T0.8 keV
300 J short pulse doubled the core plasma temp to
0.8 keV implying 40 coupling of EPW
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A credible pathway to take FI to concept
demonstration exists

• Proof of Principle (Concept Extension)
  Significant core heating at relevant conditions
• FIREX1 (Japan)
• Concept Demonstration (Ignition/gain)
• US Facilities (?, Z, NIF) with PW

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Summary

• Short pulse (? lt 10 psec), high brightness
  lasers (B gt 1015 Watts/cm2-st) have enabled the
  new field of high energy density physics (HEDP)
• There is an increasing national and international
  interest in HEDP
• Fast Ignition exploits the physics and technology
  of HEDP
• features
• Science frontier-relativistic plasmas, etc
• Compatible with all drivers
• Flexibility in reactor concepts
• International collaborations ?
• High gain potential at sub-megajoule energies