Creation of hot dense matter in short-pulse laser-plasma interaction with tamped titanium foils

Chen, S. N.; Gregori, G.; Patel, P. K.; Chung, H.‐K.; Evans, R. G.; Freeman, R. R.; Saiz, Eduardo; Glenzer, S. H.; Hansen, Stephanie B.; Khattak, F. Y.; King, J. A.; Mackinnon, A. J.; Notley, M.; Pasley, J.; Riley, David; Stephens, R. B.; Weber, R.; Wilks, S. C.; Beg, F. N.

doi:10.1063/1.2777118

Cited by 46 publications

(23 citation statements)

References 32 publications

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“…Absorption lengths exceed the target dimensions, so that emission from the bulk target is diagnosed. K-alpha spectra from copper and titanium targets irradiated with several 100 J's of laser energy indicated increased heating up to 200 eV when the target dimension were reduced to 100 mm [11,12]. Nilson et al [13] used the ratio of K-beta to K-alpha radiation to infer bulk temperatures of a200 eV in reduced mass targets, irradiated with only 10 J of laser energy.…”

Section: Introductionmentioning

confidence: 98%

Isochoric heating of reduced mass targets by ultra-intense laser produced relativistic electrons

Neumayer

Lee

Offerman

et al. 2009

High Energy Density Physics

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a b s t r a c tWe present measurements of the chlorine K-alpha emission from reduced mass targets, irradiated with ultra-high intensity laser pulses. Chlorinated plastic targets with diameters down to 50 mm and mass of a few 10 À8 g were irradiated with up to 7 J of laser energy focused to intensities of several 10 19 W/cm 2 . The conversion of laser energy to K-alpha radiation is measured, and high-resolution spectra that allow observation of line shifts are observed, indicating isochoric heating of the target up to 18 eV. A zerodimensional 2-temperature equilibration model, combined with electron impact K-shell ionization and post processed spectra from collisional radiative calculations reproduces the observed K-alpha yields and line shifts, and shows the importance of target expansion due to the hot electron pressure.

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Section: Introductionmentioning

confidence: 98%

Isochoric heating of reduced mass targets by ultra-intense laser produced relativistic electrons

Neumayer

Lee

Offerman

et al. 2009

High Energy Density Physics

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“…When hot electron contribution is considered, it is assumed to be a small perturbation on the ionization balance and taken to be around 1% of the background electron density. 5,6 Recently, there has been some effort to highlight the effect of hot electron distributions on K-shell lines and ionization balance in atomic models. 12,13 However, there is still a lack of detailed study of effect of fast electron on K-shell spectra because it is difficult to fully characterize hot electrons experimentally, e.g., temperature, number density, and lifetime of the hot electrons created in the interaction are only estimated.…”

Section: Introductionmentioning

confidence: 99%

“…3 Plasmas with kilovolt temperatures and near solid densities can be produced by lasers with intensities greater than 10 19 W / cm 2 . [4][5][6] Diagnosing plasma properties in this regime is difficult, due to complex laser absorption and heating mechanisms, small spatial scales, strong spatial gradients, and rapidly evolving plasma conditions. Such considerations point to the need for fundamental studies to better characterize plasma states created by short pulse laser-matter interaction.…”

Section: Introductionmentioning

confidence: 99%

“…The plasma that is created in a solid target interacting with a short pulse laser is highly nonuniform in temperature and density [4][5][6] and consists of both thermal and hot electrons, which makes characterization a challenge. The nonuniformity arises from several factors, one of which is the laser prepulse that can ablate the front surface prior to the arrival of the main pulse.…”

Section: Introductionmentioning

confidence: 99%

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X-ray spectroscopy of buried layer foils irradiated at laser intensities in excess of 1020 W/cm2

et al. 2009

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Observations of a rapid decrease in thermal temperature as a function of depth of solid targets irradiated with a short pulse, ultrahigh-intensity laser are reported. This phenomenon is investigated using the Titan short pulse laser with intensities greater than 1020 W/cm2 interacting with buried layer targets. The longitudinal temperature profile is determined by measuring K-shell spectra from a 0.4 μm copper tracer layer placed at various depths (i.e., 0–1.5 μm) within the 2.4 μm thick target. It is observed that the line ratios (He-like K-shell lines) as a function of temperature require a consideration of at least three parameters to analyze the K-shell spectra: hot electron population, time-dependent plasma conditions, and opacity. Here, the study of the effect of these three parameters on measured spectra in the short pulse high intensity laser-matter interactions using the atomic model FLYCHK [H.-K. Chung et al., High Energy Density Phys. 1, 3 (2005)] is presented.

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“…With the advent of new excitation techniques, hot-electrons generated in 'university-scale' intense LPI experiments have been used to generate these high energy density (HED) conditions by isochorically heating reduced mass targets to tens of keV at near solid densities [2,12,13].…”

Section: Warm-dense Matter Generationmentioning

confidence: 99%

Specular Reflectivity and Hot-Electron Generation in High-Contrast Relativistic Laser-Plasma Interactions

Kemp

2013

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Ultra-intense laser (> 10 18 W/cm 2 ) interactions with matter are capable of producing relativistic electrons which have a variety of applications in state-of-the-art scientific and medical research conducted at universities and national laboratories across the world. Control of various aspects of these hot-electron distributions is highly desired to optimize a particular outcome. Hot-electron generation in low-contrast interactions, where significant amounts of under-dense pre-plasma are present, can be plagued by highly non-linear relativistic laser-plasma instabilities and quasi-static magnetic field generation, often resulting in less than desirable and predictable electron source characteristics. High-contrast interactions offer more controlled interactions but often at the cost of overall lower coupling and increased sensitivity to initial target conditions. An experiment studying the differences in hot-electron generation between high and low-contrast pulse interactions with solid density targets was performed on the Titan laser platform at the Jupiter Laser Facility at Lawrence Livermore National Laboratory in Livermore, CA. To date, these hot-electrons generated in the laboratory are not directly observable at the source of the interaction. Instead, indirect studies are performed using state-of-the-art simulations, constrained by the various experimental measurements. These measurements, more-often-than-not, rely on secondary processes generated by the transport of these electrons through the solid density materials which can susceptible to a variety instabilities and target material/geometry effects. Although often neglected in these types of studies, the specularly reflected light can provide invaluable insight as it is directly influenced by the interaction.In this thesis, I address the use of (personally obtained) experimental specular reflectivity measurements to indirectly study hot-electron generation in the context of high-contrast, ii relativistic laser-plasma interactions. Spatial, temporal and spectral properties of the incident and specular pulses, both near and far away from the interaction region where experimental measurements are obtained, are used to benchmark simulations designed to infer dominant hot-electron acceleration mechanisms and their corresponding energy/angular distributions. To handle this highly coupled interaction, I employed particle-in-cell modeling using a wide variety of algorithms (verified to be numerically stable and consistent with analytic expressions) and physical models (validated by experimental results) to reasonably model the interaction's sweeping range of plasma densities, temporal and spatial scales, G. E. Kemp, et al, Experimental and LSP modeling of pre-pulse effects on the laser-plasma interaction by a 527 nm laser pulse,

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Creation of hot dense matter in short-pulse laser-plasma interaction with tamped titanium foils

Cited by 46 publications

References 32 publications

Isochoric heating of reduced mass targets by ultra-intense laser produced relativistic electrons

Isochoric heating of reduced mass targets by ultra-intense laser produced relativistic electrons

X-ray spectroscopy of buried layer foils irradiated at laser intensities in excess of 1020 W/cm2

Specular Reflectivity and Hot-Electron Generation in High-Contrast Relativistic Laser-Plasma Interactions

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