Presented at the 15 th International Symposium on Heavy Ion Driven Inertial Confinement Fusion in Princeton, June 7, 2004 by Matthias Geissel 1,2, Markus Roth 2, M. Allen 3, P. Audebert 4, M. Basko 5, A. Blažević 2, E. Brambrink 2, J. Cobble 6, T.E. Cowan 7, M. Cuneo 1, J.C. Fernández 6, J. Fuchs 4,7, J.-C. Gauthier 4, M. Hegelich 6, S. Karsch 8 1 Sandia National Laboratories, Albuquerque 2 Darmstadt University of Technology & GSI, Darmstadt 4 LULI – École Polytechnique, Palaiseau 7 University of Nevada, Reno & GA, San Diego 8 Rutherford Appleton Laboratory 3 University of California, Berkeley TU Darmstadt 6 Los Alamos National Laboratory UN Reno Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL Inst. for Theor. and Exp. Physics, Moscow

1.Intro: Combining Lasers and Ion Drivers 2.Concept: How Does It Work? 3.Experiments: Probing the Models 4.Fast Ignition: Some Considerations 5.New Projects: Perspectives at SNL

Laser Drivers + High Power Densities + Good Pulse Shaping – Low Driver Efficiency – Low Repetition Rate Heavy Ion Drivers + High Efficiency + Beam-Target Coupling + High rep-Rate – Lower Power – Lower Focusability e-e- FAST IGNITOR + Relieved compression requirements - Problematic energy transport from critical density layer to core via hot electrons PROTON fuel pellet hohlraum

Mechanism gold foil Pre Pulse / ASE MAIN >10 19 W/cm 2 e-e protons return current V/m TNSA Target Normal Sheath Acceleration TNSA Target Normal Sheath Acceleration + - Acceleration of surface contaminants 1.Influence of sheath formation (bulk material/conductivity) 2.Influence of rear surface (roughness/features/curvature) electron cloud pre-plasma

1.Target: Investigation of different materials Investigation of foil curvatures Investigation of surface structures 2.Beam: Spatial distribution Emittance Energy distribution Experimental Issues

ion spectrometer* and / or Thomson parabola* Setup of the Experiment RCF* * radiochromic film 0° or 13° fs TW protons

Conductivity laser goldplastic high conductivity well established e - -sheath intense, collimated protons smooth proton beam no conductivity filamented e – and proton beams low proton intensity

1D Defocusing 60µm gold wire apertures for ion spectrometers protons RCF laser

Rear Surface Features laser Example: Line Pattern false color picture of the RCF response (beam imprint) interpretation proton source size ~60µm * emittance < 0.01 mm mrad * for protons > 10 MeV: source size < 15µm e N < mm mrad

Proton Energy Spectra Tayloring the energy spectrum of laser generated protons is an important issue to be solved (mono-energetic ions for FI).

Fast Ignitor Scenario Conversion efficiency: 1-10% so far (increasing with laser performance). Need for a Multi-Beam-Ignitor. Conversion window as concave multi-lenslets. Production Target Issues: Cold rear surface Acceleration vacuum gap Proximity to the hohlraum/capsule Thin shield must protect from driver- induced soft X-rays Multiple (Multi-) PW Beams Radiation Shields

Production Target Stability Planar Gold Wall Response on Driver Radiation (M. Basko) 50µm 15µm 30µm IGNITION ,01 0,1 1 R rear (t) R (mm), T e (eV) time (ns) T e,rear (t) a 50µm shield is displaced by 230µm at the time of ignition (maximum compression) the shield is heated up to 2-3 eV at the time of ignition 15µm 30µm 50µm Petawatt-beams DT capsule proton beams p + target main shield main cavity 600 µm 2 nd shield

1.Ultra intense lasers can generate ion beams of superior beam quality 2.TNSA is the primary process 3.Spatial distribution and divergence ca be taylored 4.Fast Ignition: Multiple PW laser necessary Sophistically shaped p + -production target Careful heat shielding essential Complex but feasible scenario Conclusion

Sandia Multi-TW Facilities OPCPA at High Energies General Atomics custom design OPCPA front end: 10Hz. Nd:glass (phosphate) rod amplifiers push to 1 shot / 15 min. Nd:glass (phosphate) slab amplifier (Beamlet design) push to J (depending on available gratings and compressor design). Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000

The ZBL Laser Complex Z-BeamletControl Room100 TW LaserOptics Support Facility100TW Target Area

10TW Experiments Small Scale – 15 min. Rep-Rate CCD+LDM, HeNe compressor target chamber

100TW Project Status

Petawatt Experiments Fast Ignition Experiments on Z Petawatt Target Area 100 TW Target Area