1 / 26

Ion driven Fast Ignition

Ion driven Fast Ignition. B. Manuel Hegelich LULI July 2006. Transport, stopping and energy loss of MeV/amu ions in WDM. Experimental Team. Experiment: B. Manuel Hegelich, PI, P -24 Kirk A. Flippo , P-24 Cort Gautier, P-24 Juan C. Fernandez, P-24. Theory: Mark Schmitt, X-1

dick
Download Presentation

Ion driven Fast Ignition

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Ion driven Fast Ignition B. Manuel Hegelich LULI July 2006 Transport, stopping and energy loss of MeV/amu ions in WDM

  2. Experimental Team Experiment: B. Manuel Hegelich, PI, P-24 Kirk A. Flippo , P-24 Cort Gautier, P-24 Juan C. Fernandez, P-24 Theory: Mark Schmitt, X-1 Brian Albright, X-1 Lin Yin, X-1 D. Gericke, Univ. Warwick Collaborators: LULI: J. Fuchs, P. Antici, P. Audebert SNL: E. Brambrink, M. Geissel GSI: M. Schollmeier, Knut, F. Nürnberger, M. Roth LMU Munich/MPQ: J. Schreiber, A. Henig

  3. Outline • Ion-driven fast ignition: Concept, parameters, & challenges • Laser-driven stopping power experiment • Preliminary results • Summary

  4. There are 3 different envisioned FI scenarios: electrons, protons and light ions. Each has different challenges Detailed study on proton fast ignition: Temporal et al., Phys. Plas. 9 (2002) 3098 • fuel density   300 – 500 g/cm3 • Alpha-particle range sets the minimum hot-spot size (r 10 m) • realistically 25 m ion-beam diameter • Hot-spot disassembly (cS ~ r,   20 ps) • sets required power • Constrains combinations of ion-energy spread & distance between ion source & fuel Smaller ion energy spread → larger tolerable separation, less energy in ion beam required Protons N~7x1015 E~11 kJ N~4x1016 E~26 kJ

  5. Demonstration of monoenergetic ion acceleration makes carbon an interesting candidate for Fast Ignition. 30-40 MeV/u is needed due to its stopping in the hot, dense fuel plasma. FI conditions: Hotspot size is ~(25 mm)3 ne ~ 1026 cm-3, Te,start ~ 1 keV, Te,end ~ 10 keV. Modeling* of C6+ stopping in fuel yields:, 40 MeV/u initially required, 9 MeV/u after fuel started to heat, 33 MeV/u to account for losses in preplasma. • FI carbon ions are ~100x as energetic as FI protons • 100x fewer particles are needed, i.e. NC~2 x 1014 * ISAAC code (Ion Stopping At Arbitrary Coupling)Gericke et al., LPB 20, (2002)

  6. Challenges for light ion based Fast Ignition: • Requires a tailored spectrum (quasi mono-energetic ions) • Demonstrated: Hegelich et al., Nature 439, 441 (2006) • Higher ion energies (30-40 MeV/amu), conversion efficiency • Empirical scaling laws: ~2 kJ laser energy • Novel target designs • New acceleration mechanism (Yin, Hegelich et al., LPB 24, 291 (2006)) • K. Flippo (talk, Friday), B. Albright (talk, Sunday) • Particle transport and stopping in WDM • Strong theory effort: Model by Gericke, Murillo et al. • Ongoing experiments (LULI, Trident) Cleaned Pd-target 10Å graphitized source layer Monoenergetic Carbon Co-moving e- preplasma Multitude of Pd substrate Charge stages Laser pulse

  7. Ion transport and stopping in WDM Goal: investigate the stopping of MeV/nucleon ions in warm dense matter. Challenge: • Creating solid density warm dense matter (~50 eV) • WDM disassembles on ns timescales • Accelerator ion pulses have ~100ns pulse duration Solution: • Shortpulse laser isochorically heats target plasma • Shortpulse laser creates ps ion beam

  8. Ion Generation Target Refluxing hot electrons Plasma Creation Short-Pulse Dense Plasma Target + 6° TP1 Accelerating Laser Pulse - 6° TP2 Ion Beam Electron Sheath Plasma Probe Beam Proposed Beam Time LULI 2006: Ion Transport through dense plasmas by comparison of charge state and energy distributions.Estimated spectra:

  9. Ion transport in WDM, LANL-LULI Experiment @ the LULI 100TW Laser: Setup and diagnostics Isochoric heating shortpulse 0.45 ps, 8 J, 1x1017 W/cm2 Target +5° Ion acceleration shortpulse 0.35 ps, 20 J, 4x1019 W/cm2 Thomson parabolas Accelerated ions -5° Cw-cleaning laser ~10 W (LANL) Pre-shot Target diagnostics (Pyrometer, RGA) 2w probe pulse 0.35 ps, ~20mJ

  10. Target heated by 10W cw laser (532 nm) 93 Pd-Al 902 °C 92 Pd-CVD 900 °C

  11. Carbon Electron Density Gold Electron Density r(cm) r (cm) z(cm) z (cm) Carbon Burns Through Faster Than Gold • Snapshots at 50 ps after 400 fs laser pulse illumination

  12. Electron temperatures of 40-70 keV predicted by LASNEX Te [keV] 1: t = 1 ps 2: t = 10 ps 3: t = 50 ps 4: t = 100 ps 5: t = 0 ps X [cm]

  13. 1300 1000 500 0 Carbon Velocity (km/s) Gold luli33 luli34 10-5 10-4 .001 .01 0.1 1 10 100 1000 Time (ps) Velocity of Critical Surface Simulated with Lasnex • 12 m Thick Carbon and Gold Targets • Intensity of 2x1017 W/cm2 during 400 fs pulse with 100 m Ø spot size • Lower density Carbon produces higher critical surface velocity

  14. Target expansion velocities measured by shortpulse shadowgraphy

  15. Shot 88: Pd-primary (900 °C), C-secondaryCR-39 #: 85+86; Ii = 6.85e19; Ih = 2.23e17 Free streaming Passed through cold matter

  16. Shot 88: Pd-primary (900 °C), C-secondaryCR-39 #: 85+86; Ii = 6.85e19; Ih = 2.23e17 Free streaming Passed through plasma

  17. Shot 68; 88: Pd-primary (1170; 900 °C), C-secondaryCR-39 #: 46, 47; 85,86; Ii = 4.5e19 6.9e19; Ih = 0; 2.2e17 Free streaming Passed through cold matter 47 86 46 Passed through plasma 47 + 86 85

  18. Preliminary Summary • Experiment was designed to be a proof-of-principle for ion stopping in WDM with laser-driven ions • TP + target alignment tricky but possible • New pyrometer works reliably • Reproducable free streaming ion distribution • Clear difference between stopping in cold target and plasma • Need for better diagnostic for target plasma • Preliminary results seem to disagree with model • Monoenergetic carbon reproduced on different laser system, we know have results from both Trident and LULI 100TW

  19. B fields & collective ion modes dense plasma beam knocked-on light ion Zeff (x) collisions with ions collisions with e- ions ion stopping energy deposition collective e- modes electrons * D. O. Gericke, Laser Part. Beams 20 (2003) 471; Gericke & Schlanges, Phys. Rev. E 67 (2003) 037401 . Theory of ion stopping in plasmas is only poorly understood: • Validate models of atomic-physics evolution of beam ions in dense plasmas (ionization, charge X & recombination). • Validate models of knock-on cascades (heavy-ion collisions with light ions) • Validate reduced models of beam-energydeposition (e.g., Gericke et al.*) • Critical for “slow” ions, i.e., MeV/nucleon ions near the end of their range. • Fluid beam-plasma instabilities from interaction of beam & plasma electrons

  20. Shot 68: Pd-primary (1170 °C), C-secondary, not heated CR-39 #: 47; Ii = 4.5e19 W/cm2; Ih = 0, free streaming

  21. Shot 68: Pd-primary (1170 °C), C-secondary, not heated, CR-39 #: 46; Ii = 4.5e19 W/cm2; Ih = 0, blocked by secondary

  22. Shot 88: Pd-primary (900 °C), C-secondaryCR-39 #: 86; Ii = 6.85e19; Ih = 2.23e17, free streaming

  23. Shot 88: Pd-primary (900 °C), C-secondaryCR-39 #: 85; Ii = 6.9e19; Ih = 2.2e17, blocked by secondary

  24. Knut 76

  25. Knut 77

More Related