Experimental study of ejecta from shock melted lead

Chen, Yongtao; Hu, Haibo; Tang, Tiegang; Ren, Guowu; Li, Qingzhong; Wang, Rongbo; Buttler, W. T.

doi:10.1063/1.3692570

Cited by 83 publications

(23 citation statements)

References 19 publications

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“…This is in contradiction with the common postulates that (i) the particles are created instantaneously at the reflection of the shockwave onto the free surface [11,15] and (ii) the strain rate is spatially distributed over the depth of the jet [16,20]. Moreover, our simulations show that even with a single perturbation wavelength, the particles are distributed in sizes, unlike the assumption in Ref.…”

Section: Discussioncontrasting

confidence: 54%

“…Indeed, when the release waves issued from the reflection of the shockwave onto the free surface reach the backside of our crystal, the system comes off the piston that was applied to support the shock. Then the crystal becomes isolated, and when the sheets are ejected, it loses a very small part of its velocity (momentum conservation) that can no more be compensated by the piston, unlike what occurs in hydro computations [1,[17][18] and experiments [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] where the samples have "infinite" (very large) dimensions. Other sources may also explain this difference; in particular the conditions of simulation (supported shockwave at extreme pressure).…”

Section: The Continuum Point Of Viewmentioning

confidence: 99%

“…Experimentally and numerically, the ejecta cloud has been and continues to be characterized mainly globally, at the continuum level, through the measure of the total amount of ejected mass as a function of the velocity [7][8][9][10][11][12][13][14][15][16] and by using the conservation laws of hydrodynamics in computations [1,[17][18]. From these studies, is now well admitted that the phenomenon is a limiting case of Richtmyer-Meshkov instabilities (RMIs) [1,[19][20].…”

Section: Introductionmentioning

confidence: 99%

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Mass-velocity and size-velocity distributions of ejecta cloud from shock-loaded tin surface using atomistic simulations

Durand

Soulard

2015

Journal of Applied Physics

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Abstract:The mass (volume and areal densities) versus velocity as well as the size versus velocity distributions of a shock-induced cloud of particles are investigated using large scale molecular dynamics (MD) simulations. A generic three-dimensional tin crystal with a sinusoidal free surface roughness (single wavelength) is set in contact with vacuum and shock-loaded so that it melts directly on shock. At the reflection of the shock wave onto the perturbations of the free surface, two-dimensional sheets/jets of liquid metal are ejected. The simulations show that the distributions may be described by an analytical model based on the propagation of a fragmentation zone, from the tip of the sheets to the free surface, within which the kinetic energy of the atoms decreases as this zone comes closer to the free surface on late times. As this kinetic energy drives (i) the (self-similar) expansion of the zone once it has broken away from the sheet and (ii) the average size of the particles which result from fragmentation in the zone, the ejected mass and the average size of the particles progressively increase in the cloud as fragmentation occurs closer to the free surface.Though relative to nanometric scales, our model may help in the analysis of experimental profiles.2

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Section: Discussioncontrasting

confidence: 54%

Section: The Continuum Point Of Viewmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Mass-velocity and size-velocity distributions of ejecta cloud from shock-loaded tin surface using atomistic simulations

Durand

Soulard

2015

Journal of Applied Physics

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“…Studies of the ejecta source also continued, with a report of work on Pb [49], and more results from the LANL Sn work [50]. The LANL source term work was extended to ejecta from a second shockwave [51,52], and the full LANL Sn ejecta set for supported and unsupported shock loading at a single finish was released [53,54].…”

Section: Smentioning

confidence: 99%

Foreword to the Special Issue on Ejecta

Buttler

Williams

Najjar

2017

J. dynamic behavior mater.

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A Brief History of Ejecta Physics 1950s and 1960sThere exists anecdotal evidence that ejecta research began in the 1950s, but little of this early research was documented publicly. In Russia, the ejecta phenomenon was first observed in plate impact experiments, and shown to be dependent on the initial surface roughness [1]. The Los Alamos PHERMEX radiographic facility was used to study the production and interaction of jets from shocked surfaces, starting from its very first shot in 1963 [2]. By 1969, Bristow and Hyde [3] describe the results of a mature program in the UK using photographic imaging of ejecta processes to infer whether melt had occurred at the surface of shocked materials. They showed that drive nonuniformity and subsurface fragmentation (spall/scabbing) were also contributory factors in determining the nature of ejecta produced. 1970sThe earliest published ejecta research was done by James Asay [4]. Asay went on to develop a non-radiographic ejecta diagnostic, the eponymous Asay foil [5]. Later, he developed a prescriptive model of ejecta, where he associated the amount of mass ejected from a shocked surface to the volume of surface defects, the rise time of the shock impulse, the yield strength of the material, and the phase of the material on release, i.e., liquid or solid [6]; interestingly he also observed that ejecta production was independent over broad ranges to the peak loading stress P S . Los Alamos National Laboratory (LANL) also became active in the development of ejecta diagnostics, as released by Hopson and Olinger [7].Ejecta physics is a young field, having developed over the last 60 years or so. Essentially, ejecta forms as a spray of dense particles generated from the free surface of metals subjected to strong shocks, but the detailed mechanisms controlling the properties of this particulate ejecta are only now being fully elucidated. The field is dynamic and rapidly growing, with military and industrial applications, and applications to areas such as fusion research.This Special Issue on Ejecta reports the current state of the art in ejecta physics, describing experimental, theoretical and computational work by research groups around the world. While much remains to be done, the dramatic recent progress in the field, some of it first reported here, means that this volume provides a particularly timely review.In this foreword, we provide a brief historical overview of the development of ejecta physics, to define the context for the work in the rest of this Special Issue.

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“…Characterizing these ejecta has long been an area of active research at Los Alamos National Laboratory and throughout the broader scientific community through both theory [1][2][3][4][5][6][7][8] and experiment [9][10][11][12][13][14][15][16][17][18][19][20]. In particular, understanding the size distribution of the ejected particles and how it is affected by the surface characteristics has been the subject of much work at Los Alamos [7,[18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Constraining ejecta particle size distributions with light scattering

Schauer

Buttler

Sorenson

et al. 2018

AIP Conference Proceedings

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Abstract. We present size distributions for particles ejected from features machined onto the surface of shocked Sn targets. The functional form of the size distributions is assumed to be log-normal, and the characteristic parameters of the distribution are extracted from the measured angular distribution of light scattered from a laser beam incident on the ejected particles. We find strong evidence for a bimodal distribution of particle sizes with smaller particles evolved from features machined into the target surface and larger particles being produced at the edges of these features. Preliminary data on ejecta transported through Helium gas at various pressures is also presented.

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Experimental study of ejecta from shock melted lead

Cited by 83 publications

References 19 publications

Mass-velocity and size-velocity distributions of ejecta cloud from shock-loaded tin surface using atomistic simulations

Mass-velocity and size-velocity distributions of ejecta cloud from shock-loaded tin surface using atomistic simulations

Foreword to the Special Issue on Ejecta

Constraining ejecta particle size distributions with light scattering

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