Application of photon Doppler velocimetry for characterization of ejecta from shock-loaded samples

Abstract

We consider the problem of recovering the physical parameters of ejecta from data of photon Doppler velocimetry (PDV). The results of PDV measurements of ejecta production from shock-loaded Pb samples are presented. Shockwaves in the samples were generated by an accelerated flyer-plate. Depending on the sample thickness, the shock-breakout pressure varied from 27.5 to 43 GPa. The ejecta transport occurred in the air. The spectral profile J(ω) of heterodyne beats underlies our analysis of the experiments. The noise-free component of |J(ω)|2 is shown to obey the transport equation which accounts for multiple scattering and absorption of the probing beam in the cloud of moving particles. This provides a means for theoretical modeling of PDV data. Varying the values of the free-surface velocity and the parameters of the velocity distribution of ejecta, we fit the calculated spectrum to the PDV-measured one. We apply this method to time-resolved PDV spectra and, based on the ejecta optical model, recover the values of the free-surface velocity, the areal density, and the density-velocity distribution of ejecta.

Dynamics behavior of porous tin under strong shockwave impact

“…强冲击作用下的金属材料动态破碎过程, 既包含 简单的单次加载微喷、层裂/微层裂破碎 [1][2][3][4][5][6][7][8][9][10][11][12][13] , 也有复 杂多次加载产生的表面微射流、主体区域反复冲击再 破碎、主体区域对微射流颗粒回收等一系列复杂过 程 [14][15][16] , 是耦合材料特性、加载状态、样品初始状态 等多因素的复杂多尺度问题, 在惯性约束核聚变、冲 击防护等领域有重要的工程价值和科学意义, 最近几 十年被广泛研究 [17][18][19] .…”

Reconstruction and interpretation of photon Doppler velocimetry spectrum for ejecta particles from shock-loaded sample in vacuum

“…10,11 Many experimental approaches have attempted to measure the ejection production, such as the Asay foil, 3,12 foam recovery, 13 piezoelectric probes, 4,14 Fraunhofer holography, 15,16 X-ray/proton radiography, 2,17 Mie scattering, 17,18 , and photon Doppler velocimetry (PDV). [19][20][21][22][23][24][25] The main quantities of interest are the particles' velocity, diameter, and total area mass. Most approaches can only measure some of these ejecta parameters.…”

“…However, in realworld conditions, these approaches are hard to apply simultaneously because of limitations on the experimental space or configuration. Recently, PDV has attracted considerable attention 21,22,25 owing to its ability to recover the total area mass and the distributions of particle velocity and diameter at the same time. In addition, the light path of PDV is rather concise and its application is convenient.…”

“…Fedorov et al 24 discussed the influence of different particle sizes on the spectrogram boundary in further detail. Recently, Franzkowiak et al 22 and Andriyash et al 21,25 reconstructed the light field of ejecta and obtained the simulated PDV spectrum using single-and multiple-scattering theory, respectively. They varied the particles' parameters and fitted the simulated PDV spectrum to the experimental data.…”

“…Franzkowaik et al 22 and Andriyash et al 21,25 proposed similar approaches for recovering the ejecta parameters from the PDV spectrum through reconstruction and then fitting. However, some assumptions were introduced in the reconstruction of the light field.…”