Erratum:<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>K</mml:mi><mml:mi>α</mml:mi></mml:msub></mml:math>fluorescence measurement of relativistic electron transport in the context of fast ignition [Phys. Rev. E<b>69</b>, 066414 (2004)]

Stephens, R. B.; Snavely, R.; Aglitskiy, Y.; Amiranoff, F.; Andersen, Charlotte Uggerhøj; Batani, D.; Baton, S. D.; Cowan, T. E.; Freeman, R. R.; Hall, Tom; Hatchett, S.; Hill, J.M.; Key, M. H.; King, J. A.; Koch, J. A.; Koenig, Marianne; Mackinnon, A. J.; Lancaster, K. L.; Martinolli, E.; Norreys, P.; Perelli-Cippo, E.; Gloahec, M. Rabec Le; Rousseaux, C.; Santos, Jorge Juan Carrillo; Scianitti, F.

doi:10.1103/physreve.71.039901

Cited by 39 publications

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“…As shown in previous work [17] there is direct correspondence between the measured K at a given point in the image and the calculated hot electron density. The energy lost per K event is small compared to the average energy of the hot electrons; hence the summation can be performed over the electron distribution alone, neglecting losses due to K production and significantly simplifying the calculation.…”

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confidence: 78%

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Limitation on Prepulse Level for Cone-Guided Fast-Ignition Inertial Confinement Fusion

MacPhee¹,

Divol²,

Kemp³

et al. 2010

Phys. Rev. Lett.

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105

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The viability of fast-ignition (FI) inertial confinement fusion hinges on the efficient transfer of laser energy to the compressed fuel via multi-MeV electrons. Preformed plasma due to the laser prepulse strongly influences ultraintense laser plasma interactions and hot electron generation in the hollow cone of an FI target. We induced a prepulse and consequent preplasma in copper cone targets and measured the energy deposition zone of the main pulse by imaging the emitted K radiation. Simulation of the radiation hydrodynamics of the preplasma and particle in cell modeling of the main pulse interaction agree well with the measured deposition zones and provide an insight into the energy deposition mechanism and electron distribution. It was demonstrated that a under these conditions a 100 mJ prepulse eliminates the forward going component of $2-4 MeV electrons. Cone-guided fast-ignition inertial confinement fusion (FI) depends on the efficient transfer of laser energy to a forward directed beam of $2 MeV electrons at the tip of a hollow cone embedded in the side of an inertialconfinement fusion fuel capsule [1]. This scheme is particularly susceptible to laser prepulse [2,3] as the cone wall confines the expanding preformed plasma [4,5] increasing both density scale lengths and laser beam filamentation [6].The igniter laser pulse requirements for fast ignition depend on the conversion efficiency from laser energy to hot electrons [7], the electron energy spectrum [8], the electron transport efficiency to the ignition hot spot [9,10], and the electron energy deposition efficiency in the hot spot [10]. The required laser energy has been estimated at approximately 100 kJ in a 20 ps pulse [1,11]. Since the ignition hot spot diameter is $40 m, the cone tip must be similar in diameter and the laser intensity $4 Â 10 20 W=cm 2 . Existing petawatt class laser systems deliver up to 1 kJ with typical energy contrast $1 Â 10 À5 and with nonlinear devices this ratio can be improved by a further order of magnitude [12]. Contrast due to amplified superfluorescence and spontaneous emission is independent of the final laser energy; hence, for an ignition pulse of 100 kJ the prepulse energy on target could range from 100 mJ to 1 J. Recent work by Baton et al. [5] has shown that some amount of prepulse can strongly affect coupling to cones; however, a detailed understanding of this limit has not been reported.In this Letter we report recent studies of laser interactions with hollow cone targets comparing simulations and experiments in conditions approaching full fast ignition (FI) using prepulse up to 100 mJ with main pulse irradiance $10 20 W cm À2 for picosecond durations. These parameters were accessible using the Titan laser at LLNL, which delivers ð150 AE 10Þ J in ð0:7 þ = À 0:2Þ ps at 1 m with $10% of the energy deposited above an intensity of $10 20 W cm À2 at best focus, as described in [13].We compare coupling for two well-characterized prepulse conditions: (1) an intrinsic Titan laser prepulse with ð7:5 AE 3Þ mJ in 1.7 n...

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“…In the experiment the time integrated distribution of K fluorescence radiation from copper cone targets was measured using a spherically bent quartz crystal x-ray microscope tuned to Cu K radiation at 8048 eV with $5:2 eV bandwidth [16][17][18] and a magnification of Â7 as shown in Fig. 1.…”

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confidence: 99%

Limitation on Prepulse Level for Cone-Guided Fast-Ignition Inertial Confinement Fusion

MacPhee¹,

Divol²,

Kemp³

et al. 2010

Phys. Rev. Lett.

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105

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“…The REB geometry was measured using a 2D Cu-K imaging technique [27], showing a 22 AE 6 cone half-angle divergence independent of the sample state. These results are reported elsewhere [28].…”

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Relativistic High-Current Electron-Beam Stopping-Power Characterization in Solids and Plasmas: Collisional Versus Resistive Effects

et al. 2012

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We present experimental and numerical results on intense-laser-pulse-produced fast electron beams transport through aluminum samples, either solid or compressed and heated by laser-induced planar shock propagation. Thanks to absolute K yield measurements and its very good agreement with results from numerical simulations, we quantify the collisional and resistive fast electron stopping powers: for electron current densities of % 8 Â 10 10 A=cm 2 they reach 1:5 keV= m and 0:8 keV= m, respectively. For higher current densities up to 10 12 A=cm 2 , numerical simulations show resistive and collisional energy losses at comparable levels. Analytical estimations predict the resistive stopping power will be kept on the level of 1 keV= m for electron current densities of 10 14 A=cm 2 , representative of the full-scale conditions in the fast ignition of inertially confined fusion targets. In the fast ignition (FI) scheme of inertial confinement fusion, a relativistic electron beam (REB) heats the compressed core and ignites the fusion reactions in a capsule of deuterium and tritium [1]. This REB is generated at the critical density surface, or at the cone tip of a cone-embedded imploded capsule [2] by a high-intensity (% 10 20 W=cm 2 ) and high-energy ($100 kJ) laser. The REB source has a total kinetic energy & 40% of the laser energy [3][4][5] and a mean kinetic energy of 1-2 MeV (to provide an efficient coupling to the dense core). The REB transports energy from the generation region (with density and temperature in the level of a few g=cm 3 and a few eV, respectively) to the high-density ($ 400 g=cm 3 ) and hightemperature ($ 300 eV) core, where it must deliver a minimum of 20 kJ to heat the fuel to thermonuclear temperatures ($ 5-10 keV) [6]. The energy transport efficiency can be limited by such physical processes as collisional or collective energy loss [7], divergence [8,9], filamentation [10][11][12], etc. The energy losses over the highly inhomogeneous electron transport zone should be accurately predicted for a successful full-scale FI design. In particular, the REB stopping power should be limited to a few keV= m over the $100 m standing-off distance between the REB source and the imploded core.The work presented here aims at characterizing the REB stopping power in dense media in underscaled experimental conditions. The measurements are used to benchmark a REB transport code. The tested transport media, ranging from solid to warm dense matter, are much denser than the injected REB, being reasonable to assume an efficient neutralization of the injected current (j h ) by a counterstreaming current (j e ) of background thermal electrons (j h % Àj e ). Under these conditions, the numerical description of the REB transport often uses the so-called hybrid approach, where the incident and weakly collisional electrons are modeled kinetically and the highly collisional return current is described as an inertialess fluid [10,13,14].Most of the REB transport experiments carried out up to now have used solid targets [8,15...

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“…As a bright, narrow band, energetic x-ray source, laser driven x-ray is adapted for various applications including probing of dense matters treated in the field of high energy density physics [1]. Moreover, laser driven x-ray sources have been widely used for inner shell photoionization [2], ultra-fast biomedical imaging, lattice dynamics probing, and basic research in radiation biology.…”

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confidence: 99%

Efficient multi-keV X-ray generation from high-contrast laser plasma interaction

Zhang

Nishimura

Nishikino³

et al. 2013

EPJ Web of Conferences

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Abstract. K line emission from Mo was experimentally and theoretically studied using clean, ultrahighintensity femtosecond laser pulses. The absolute yields of K x-rays at 17 keV from Mo were measured as a function of the laser pulse contrast ratio and irradiation intensity. Significantly enhanced K yields were obtained by employing high contrast ratio at optimum irradiance. Conversion efficiencies of 4.28 × 10 −5 /sr, the highest values obtained to date, was demonstrated with contrast ratios in the range of 10 −10 to 10 −11 .

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Erratum:Kαfluorescence measurement of relativistic electron transport in the context of fast ignition [Phys. Rev. E69, 066414 (2004)]

Cited by 39 publications

References 0 publications

Limitation on Prepulse Level for Cone-Guided Fast-Ignition Inertial Confinement Fusion

Limitation on Prepulse Level for Cone-Guided Fast-Ignition Inertial Confinement Fusion

Relativistic High-Current Electron-Beam Stopping-Power Characterization in Solids and Plasmas: Collisional Versus Resistive Effects

Efficient multi-keV X-ray generation from high-contrast laser plasma interaction

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