Proton Radiography of Inertial Fusion Implosions

A distinctive way of quantitatively imaging inertial fusion implosions has resulted in the characterization of two different types of electromagnetic configurations and in the measurement of the temporal evolution of capsule size and areal density. Radiography with a pulsed, monoenergetic, isotropic proton source reveals field structures through deflection of proton trajectories, and areal densities are quantified through the energy lost by protons while traversing the plasma. The two field structures consist of (i) many radial filaments with complex striations and bifurcations, permeating the entire field of view, of magnetic field magnitude 60 tesla and (ii) a coherent, centrally directed electric field of order 109 volts per meter, seen in proximity to the capsule surface. Although the mechanism for generating these fields is unclear, their effect on implosion dynamics is potentially consequential.

[1]  R. P. Drake,et al.  Experimental astrophysics with high power lasers and Z pinches , 2004 .

[2]  A. Nishiguchi.  Effects of Self-Generated Magnetic Field on Rayleigh–Taylor Instability , 2002 .

[3]  J. R. Rygg,et al.  Measuring E and B fields in laser-produced plasmas with monoenergetic proton radiography. , 2006, Physical review letters.

[4]  T. C. Sangster,et al.  Direct-drive fuel-assembly experiments with gas-filled, cone-in-shell, fast-ignitor targets on the OMEGA Laser , 2005 .

[5]  R. Petrasso,et al.  Charged-particle stopping powers in inertial confinement fusion plasmas. , 1993, Physical review letters.

[6]  J. Meyer-ter-Vehn,et al.  The physics of inertial fusion - Hydrodynamics, dense plasma physics, beam-plasma interaction , 2004 .

[7]  J. R. Rygg,et al.  Observation of megagauss-field topology changes due to magnetic reconnection in laser-produced plasmas. , 2007, Physical review letters.

[8]  H. Shiraga,et al.  Nuclear fusion: Fast heating scalable to laser fusion ignition , 2002, Nature.

[9]  M. Haines.  Magnetic-field generation in laser fusion and hot-electron transport , 1986 .

[10]  O. Willi,et al.  Filamentation on laser irradiated spherical targets , 1981 .

[11]  P. Norreys,et al.  Proton radiography of a laser-driven implosion. , 2006, Physical review letters.

[12]  Epstein,et al.  Effect of laser illumination nonuniformity on the analysis of time-resolved x-ray measurements in uv spherical transport experiments. , 1987, Physical review. A, General physics.

[13]  J. Nuckolls,et al.  Laser Compression of Matter to Super-High Densities: Thermonuclear (CTR) Applications , 1972, Nature.

[14]  Thermal Instability and Magnetic Field Generated by Large Heat Flow in a Plasma, Especially under Laser-Fusion Conditions , 1981 .

[15]  T. Tajima,et al.  Magnetic Field Generation by the Rayleigh-Taylor Instability , 1978 .

[16]  Michael D. Perry,et al.  Ignition and high gain with ultrapowerful lasers , 1994 .

[17]  Kunioki Mima,et al.  Ablation Nonuniformity on Laser Irradiated Pellet and Collisional Hot Electron Filamentation , 1980 .

[18]  B Yaakobi,et al.  Editor: I. I. Sobelman. X-Ray Plasma Spectroscopy and the Properties of Multi-Charged Ions (Volume 179, Proceedings of the Lebedev Physics Institute), (NOVA Science Publishers, Inc., New York, 1988) 256 pages, $87.00 , 1989 .

[19]  W. Kruer,et al.  The Physics of Laser Plasma Interactions , 2019 .

[20]  Peter A. Amendt,et al.  Monoenergetic proton backlighter for measuring E and B fields and for radiographing implosions and high-energy density plasmas (invited) , 2006 .

[21]  Chih-Wen Liu,et al.  The Roughness-Enhanced Light Emission from Metal-Oxide-Silicon Light-Emitting Diodes Using Very High Vacuum Prebake , 2002 .