Measuring shock-bang timing and ρR evolution of D3He implosions at OMEGA

Frenje, J. A.; Li, C. K.; Séguin, F. H.; Deciantis, J. L.; Kurebayashi, S.; Rygg, J. R.; Petrasso, R. D.; Delettrez, J. A.; Glebov, V. Yu.; Stoeckl, C.; Marshall, F. J.; Meyerhofer, D. D.; Sangster, T. C.; Smalyuk, V. A.; Soures, J. M.

doi:10.1063/1.1695359

Cited by 43 publications

(46 citation statements)

References 24 publications

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“…The timing was confirmed by the proton temporal diagnostic (PTD), which measures the absolute time of proton emission from the backlighter. 19 The proton fluence structures evolve as a result of the generation, growth, and interaction of magnetic field structures. In the top half of the images, the apparent bubble size (the radius of high proton fluence) increases rapidly due to the radial expansion of the bubble and the strengthening of the path-integrated magnetic fields.…”

Section: Resultsmentioning

confidence: 99%

First experiments probing the collision of parallel magnetic fields using laser-produced plasmas

Rosenberg

Fox

et al. 2015

Physics of Plasmas

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Novel experiments to study the strongly-driven collision of parallel magnetic fields in β∼10, laser-produced plasmas have been conducted using monoenergetic proton radiography. These experiments were designed to probe the process of magnetic flux pileup, which has been identified in prior laser-plasma experiments as a key physical mechanism in the reconnection of anti-parallel magnetic fields when the reconnection inflow is dominated by strong plasma flows. In the present experiments using colliding plasmas carrying parallel magnetic fields, the magnetic flux is found to be conserved and slightly compressed in the collision region. Two-dimensional (2D) particle-in-cell (PIC) simulations predict a stronger flux compression and amplification of the magnetic field strength, and this discrepancy is attributed to the three-dimensional (3D) collision geometry. Future experiments may drive a stronger collision and further explore flux pileup in the context of the strongly-driven interaction of magnetic fields.

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Section: Resultsmentioning

confidence: 99%

First experiments probing the collision of parallel magnetic fields using laser-produced plasmas

Rosenberg

Fox

et al. 2015

Physics of Plasmas

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“…The capsule diameter is small, at about 440 µm, in order to yield a smaller-than-usual burn radius for improved spatial resolution in the radiograph. A comprehensive set of diagnostics are used to characterize the implosion, including both proton-emission and x-ray-emission images for studying the size of the imploded capsule and its burn region, spectrometers for measuring the proton energy spectrum 12,16,17 , and a proton temporal diagnostic for measuring the bang time and burn duration 12,21 . Each fusion product is monoenergetic (Fig.…”

Section: Iia a Monoenergetic Proton Backlightermentioning

confidence: 99%

Proton radiography of dynamic electric and magnetic fields in laser-produced high-energy-density plasmas

Séguin

Frenje

et al. 2009

Physics of Plasmas

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Time-gated, monoenergetic-proton radiography provides unique measurements of the electric (E) and magnetic (B) fields associated with laser-foil interactions, imploded inertial-confinement-fusion capsules, and laser-irradiated hohlraums. These experiments resulted in the first observations of several new and important features previously unrealized: first, observations of the generation, decay dynamics, instabilities and topology change of megagauss B fields on laser-driven planar plastic foil; second, the observation of radial E fields inside the imploding capsule which are initially directed inward, reverse direction near deceleration onset, and are likely related to the evolution of the electron pressure gradient; third, the observation of many radial filaments with complex electromagnetic field striations, permeating the entire field of view, and fourth, the observation of dynamic E field associated with laser-irradiated gold hohlraums. The physics behind and implications of such observed fields are discussed.

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“…A second measurement of T i was obtained for each implosion from the DD-D 3 He yield ratio, and the T i values and uncertainties used in this Letter are weighted averages of these two measurements. D 3 He and DD burn profiles were measured with the proton core imaging system [31], and the D 3 He and DD burn duration was measured with the particle temporal diagnostic and neutron temporal diagnostic (NTD) [32,33], respectively. A secondary-neutron yield relative to the primary neutron yield (Y 2n =Y 1n ) was also measured for a D 3 He-fuel ρR determination [34].…”

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Measurements of Ion Stopping Around the Bragg Peak in High-Energy-Density Plasmas

Frenje

Grabowski

et al. 2015

Phys. Rev. Lett.

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For the first time, quantitative measurements of ion stopping at energies around the Bragg peak (or peak ion stopping, which occurs at an ion velocity comparable to the average thermal electron velocity), and its dependence on electron temperature (T e ) and electron number density (n e ) in the range of 0.5-4.0 keV and 3 × 10 22 to 3 × 10 23 cm −3 have been conducted, respectively. It is experimentally demonstrated that the position and amplitude of the Bragg peak varies strongly with T e with n e . The importance of including quantum diffraction is also demonstrated in the stopping-power modeling of high-energy-density plasmas. A fundamental understanding of DT-alpha stopping in high-energy-density plasmas (HEDP) is essential to achieving hot-spot ignition at the National Ignition Facility (NIF) [1]. This requires accurate knowledge about the evolution of plasma conditions and the DT-alpha transport and energy deposition in plasmas for a wide range of electron (T e ) and ion temperatures (T i ) spanning from tens of eV to tens of keV, and electron number densities (n e ) from ∼10 21 to ∼10 26 cm −3 .Over the last decades, ion stopping in weakly coupled to strongly coupled HEDP has been subject to extensive analytical and numerical studies [2-10], but only a limited set of experimental data exists to validate these theories. Most previous experiments also used only one type of ion with relatively high initial energy, in plasmas with n e < 10 23 cm −3 and T e < 60 eV [11][12][13][14][15][16][17][18][19][20][21]. In addition, none of these experiments probed the detailed characteristics of the Bragg peak (or peak ion stopping), which occurs at an ion velocity comparable to the average thermal electron velocity. To the best of our knowledge, only one experimental attempt to do this was made by Hicks et al. where the birth energies shown in the parentheses are for a "zero temperature" plasma [23]. From the observed energy losses of these ions, Hicks et al. were able to describe qualitatively the behavior of the ion stopping for one plasma condition. The work described here makes significant advances over previous experimental efforts, by quantitatively assessing the characteristics of the ion stopping around the Bragg peak for different HEDP conditions. This was done through accurate measurements of energy loss of the four ions, produced in reactions (1) and (2). The new experiment, carried out at the OMEGA laser [24], involved implosions of eighteen thin SiO 2 capsules filled with equimolar deuterium-3 He gas. The capsule shells were 850 to 950 μm in diameter, 2.1 to 2.8 μm thick, and had an initial gas-fill pressure ranging from 3 to 27 atm. These capsules were imploded with sixty laser beams that uniformly delivered up to 10.6 kJ to the capsule in a 0.6-ns or 1-ns square pulse, resulting in a laser intensity on capsule up to ∼4 × 10 14 W=cm 2 [25]. Table I lists the capsule and laser parameters, along with some measured and inferred implosion parameters for a subset of four implosions discussed in detail in this...

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Measuring shock-bang timing and ρR evolution of D3He implosions at OMEGA

Cited by 43 publications

References 24 publications

First experiments probing the collision of parallel magnetic fields using laser-produced plasmas

First experiments probing the collision of parallel magnetic fields using laser-produced plasmas

Proton radiography of dynamic electric and magnetic fields in laser-produced high-energy-density plasmas

Measurements of Ion Stopping Around the Bragg Peak in High-Energy-Density Plasmas

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