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Imploding cone-in-shell capsule

Proton Radiography of Electromagnetic Fields in Laser-Produced High-Energy-Density Plasmas. Protons per unit area on detector. protons. 2.7 mm. Imploding cone-in-shell capsule. 15-MeV proton backlighter. Imaging detector. HEDLP Workshop Washington DC August 08. C. K. Li MIT.

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Imploding cone-in-shell capsule

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  1. Proton Radiography of Electromagnetic Fields in Laser-Produced High-Energy-Density Plasmas Protons per unit area on detector protons 2.7 mm Imploding cone-in-shell capsule 15-MeV proton backlighter Imaging detector HEDLP Workshop Washington DC August 08 C. K. Li MIT FSC

  2. Summary Time-gated, monoenergetic proton radiography provides unique measurements of E+B fields in laser-produced HED plasmas • Radiography of laser-foil interactions: • Observation generations of ~106 gauss B field and 109 V/m E field • Observation of decay dynamics and instabilities of MG B field • Observation of field topology change due to magnetic reconnection • Radiography of direct-drive cone-in-shell/spherical implosions: • Observation of radial, filamentary structures with complex striations and bifurcations, of B field magnitude 0.6×106 gauss • Observation of radial E field of order 109 V/m and its direction reversal • Radiography of laser-irradiated gold hohlraums: • Observation of ~106 gauss B field and its evolution • Observation of ~109 V/m E field and its evolution MIT MIT

  3. Collaborators LLE-UR R. Betti J. Delettrez V. Goncharov J. Knauer F. Marshall D. Meyerhofer V. Smalyuk MIT F. Séguin J. Frenje R. Petrasso M. Manuel (G) D. Casey (G) N. Sinenian (G) LLNL P. Amendt O. Landen J. Rygg R. Town GA C. Back J. Kilkenny A. Nikroo FSC

  4. 6×108 0 3×1018 0 source spectrum source emission protons s protons MeV 130 ps FWHM 3% FWHM 0 0.5 1 0 10 20 (ns) (MeV) The proton source is a laser-driven glass capsule filled with D2 and 3He gas Heating of the gas during implosion leads to nuclear fusion production: Source D + 3He → 4He + p (14.7 MeV) 14.7 MeV protons Emission of 14.7 MeV D3He protons is pulsed, monoenergetic, and isotropic PRL 2006

  5. a A Radiographs of laser-generated plasma bubbles on opposite sides of a foil prove that deflecting fields are B rather than E OMEGA shot 46535 Petrasso et al APS 2007

  6. Interaction laser on for 1 ns Outer bubble Burn-through hole 0.3 ns 0.6 0.9 1.2 1.5 1.8 2.3 3.0 ns 5mm (c) (a) Bdℓ (MG-µm) Mean bubble radius (µm) (b) RMS bubble asymmetry (µm) Data and LASNEX simulations are similar with the laser on, but diverge afterwards LASNEX+LSP by R. Town 2D code LASNEX produces credible simulations of the hydrodynamics and field growth as long as the laser was on, failing only when 3D instabilities appeared. PRL 2007a

  7. 5mm 0.31 ns 0.51 ns 0 .69 ns 0.97 ns 1.24 ns 1.72 ns 2.35 ns Magnetic reconnection has been observed and quantified 5 mm Bdℓ (MG-µm) Bdℓ (MG-µm) > 95% field strength was reduced in the region where bubbles overlap 0.04 ns 0.67 ns 1.42 ns PRL 2007b

  8. Drive laser ~0.6 MG fields in these cellular structures with cell size ~ 120 μm Position (µm) Position (µm) P-P amp. ~ 5% P-P amp. ~ 18% Face-on 15-MeV radiographs show the evolution from “corrugated” to cellular structures “ linear” (2D) Diameter = 2.5 mm Thickness = 20±1 mm Modulation ~ 120 mm P-V modulation ~ 0.5 mm Petrasso et al APS 2007

  9. filamentary field structures radial focusing E-field capsule compressed by a factor of two cone shadow Radiography of a cone-in-shell capsule implosion reveals field topology and capsule compression Fluence 14 kJ laser drive Energy Rygg et al Science 2008

  10. Fluence 3 mm Time-gated proton radiography of direct-drive ICF spherical implosions provides the spatial structure and time evolution of E+B fields Drive laser Seguin et al APS 2007

  11. 0.8 ns 1.2 ns 1.4 ns 1.6 ns 1.9 ns 2.1ns The reversal of proton fluence focusing indicates the direction change of a self-generated radial E field 1015 1010 105 0 -105 -1010 -1015 Data E (V/m) Simulation PRL 2008

  12. before reconnection B 7mm 2mm Radiograph E+B fields generated inside Au hohlraums with protons (DD and D3He) and with alphas (D3He) 10 beams (1ns-square,SG4+SSD) from Cone 3 drive the hohlraum 21 beams drive the backlighter OMEGA-Scale 1.5 after reconnection B • Fields are very important for : • understanding ignition experiments at the National Ignition Facility. • laboratory astrophysics of plasmas with lower β (~1)

  13. Protons μm-2 2.6 mm t = 0.52 ns • Observation of ~106 gauss B field and ~109 V/m E field and their temporal evolution have been made LASNEX+LSP simulation by R. Town

  14. Summary Time-gated, monoenergetic proton radiography provides unique measurements of E+B fields in laser-produced HED plasmas • Radiography of laser-foil interactions: • Observation generations of ~106 gauss B field and 109 V/m E field • Observation of decay dynamics and instabilities of MG B field • Observation of field topology change due to magnetic reconnection • Radiography of direct-drive cone-in-shell/spherical implosions: • Observation of radial, filamentary structures with complex striations and bifurcations, of B field magnitude 0.6×106 gauss • Observation of radial E field of order 109 V/m and its direction reversal • Radiography of laser-irradiated gold hohlraums: • Observation of ~106 gauss B field and its evolution • Observation of ~109 V/m E field and its evolution MIT MIT

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