1. 1 of 16 M. S. Tillack, Y. Tao, J. Pulsifer, F. Najmabadi, L. C. Carlson, K. L. Sequoia, R. A. Burdt, M. Aralis Laser-matter interactions and IFE research at UCSD TITAN Kick-off Meeting 7-8 May 2007 San Diego, CA

2. 2 of 16 Center for Energy Research Thermal, mechanical and phase change behavior Relativistic laser plasma (fast ignition) optics damage Laser plasmas: EUV lithography, WDM and HED studies (XUV, electron transport) Laser ablation plume dynamics, LIBS, micromachining Laser-matter interactions at UCSD span a wide range of intensities and applications

3. 3 of 16 1.IFE surface heating experiments Metal mirrors for laser-IFE final optics, chamber armor thermo-mechanics 2.Ablation plume dynamics Particle acceleration, structure of plumes, mitigation, phase change physics 3.EUV lithography 13.5-nm light emission, particle transport Our group has 10 years of experience studying laser heating and ablation

4. 4 of 16 We lead the HAPL final optics program (~10 8 W/cm 2 absorbed) 1.Damage-resistant metal mirror development Coating techniques Surface finishing techniques 2. Prototypical high-cycle testing (248 nm) 3.System integration Grain motion in thick Alumiplate coating

5. 5 of 16 We recently found a surprising dependence on pulse length (2x energy in Compex) Long pulse Short pulse Predicted short-pulse Damage does not scale like pulselength 1/2 (i.e., like T max ) Is this a result of cumulative damage? ∫f(  dt mirror M109

6. 6 of 16 We are testing chamber armor for HAPL (~10 9 W/cm 2 absorbed) Time (10 -7 s) T melt 1.10 Hz exposure with Nd:YAG laser 2.High base temperature (up to 1000 ˚C) 3.Nanosecond time resolved optical thermometer 4.In-situ microscopy

7. 7 of 16 We discovered that damage is far more sensitive to temperature than  T 10 3 shots10 5 shots10 4 shots Initially 20˚C, maximum 2,500K (~2,200K  T) Initially 500˚C, maximum 3,000K (~2,200K  T)

8. 8 of 16 Laser ablation plume dynamics were originally studied for liquid wall IFE (10 10 – 10 11 W/cm 2 ) 0.01Torr 1Torr 0.1Torr 10Torr 100Torr Al (396 nm) at 18 mm in 150 mTorr air Imaging plus time-of- flight spectroscopy led to the discovery of a triple plume structure in a laser ablation plume 1.Explosive evaporation 2.Plume transport 3.Condensation

9. 9 of 16 Magnetic diversion was studied as a means to protect IFE walls 0.6 T transverse field in gap Free expansion until  th drops below ~10 Axial and cusp fields were also studied

10. 10 of 16 Our EUVL studies emphasize particle control (10 10 – 10 12 W/cm 2 ) lasers pre-plasma main plasma Pre-pulsing was found to have a dramatic effect on ion energy

11. 11 of 16 Collaborations have begun between our lab and PISCES 1.Support studies of heating and ablation for 2.Develop a laser blow-off impurity injection diagnostic 3.Perform time-resolved SXR imaging

12. 12 of 16 400 mm 40 mm 10 mm Film material:Ni Film thickness:700 nm Substrate:1 mm glass Wavelength: 1.064  m Pulse duration: 7 ns Laser Energy: 500 mJ Intensity: 1 GW/cm 2 200 mm 1 mm We began to explore laser blow-off as a diagnostic technique for MFE plasmas

13. 13 of 16 Studies were performed on the ejecta velocity and structure vs. composition, thickness, and intensity 100 ns500 ns800 ns Visible emission Shadow graphy

14. 14 of 16 Confinement of ejecta and avoidance of ionization are important to penetrate the plasma and retain spatial resolution Visible emission @500 ns FWHM=1 mm V=3 km/s Emission and witness plate shows plume is mostly neutral 10  m

15. 15 of 16 Soft x-ray imaging is proposed together with blowoff to study transport physics Stutman et al., RSI 77, 330 2006. We use similar diagnostics for EUVL research JenOptik E-mon 13.5 nm EUV mirror, NTT Advanced Technology Corp. Example lines: Li-II13.5 nm C-V24.8 nm He-II30.4 nm

16. 16 of 16 Summary We have experience and existing experimental capabilities in several topics of potential interest to TITAN:  Sub-ablation threshold rapid surface heating  Ablation plume dynamics  EUV diagnostics These capabilities are relevant to both IFE and MFE