Рассмотрена схема регистрации перемещений отражающих поверхностей методом лазерного дальномера с использованием разработанного устройства измерения задержки распространения оптического сигнала. Приведены результаты тестовых экспериментов по исследованию параметров пыления и откольного разрушения металлов при их ударно-волновом нагружении с одновременным использованием методов гетеродин-интерферометра и лазерного дальномера. A scheme of registration of displacements of reflecting surfaces by the method of laser ranging with the use of a device developed for measuring the delay of optical signal propagation is considered. Results of test experiments aimed at studying the dusting parameters and spallation fracture of metals under shock wave loading with simultaneous applications of photonic Doppler velocimetry and laser ranging methods are reported.

С помощью лазерных интерферометрических методов проведены экспериментальные исследования параметров пыления свинца, олова, меди и других металлов при их ударно-волновом нагружении в широком диапазоне давлений. Метод PDV (Photon Doppler Velocimetry) позволяет регистрировать скорость свободной поверхности, поле скоростей и удельную массу потока частиц, определять размер частиц по их торможению в газовой среде.

The results of photon Doppler velocimetry of ejecta from shock-loaded metal samples are reported. The experiments have been performed with tin and lead samples of a given thickness and a given surface roughness. The direct numerical simulation of the process of mass ejection from the surface of shock-loaded samples is performed for conditions close to experimental by the smoothed particle hydrodynamics method. The areal density and initial velocity distribution of the volume density of ejecta are determined. Using these results, we calculate the time dependence of the profile of the volume density at the expansion of the formed dust cloud to air. Applying an approach based on the transport equation for the correlation function of the scattered field, the main parameters of the velocity distribution of ejecta, areal density of ejecta, etc. are reconstructed from spectral photon Doppler velocimetry data. The experimentally observed temporal dynamics of spectra, which is caused by the drag of dust in air, is described at an appropriately chosen size dispersion of dust particles. The masses of ejecta reconstructed from experimental data are in agreement with the smoothed particle hydrodynamics results.

A heterodyne interferometer is used photon Doppler velocimetry (PDV) method to study a particle discharge from the free surface of lead samples of different roughness under a shock-wave load. In experiments, the velocity of the free surface of samples and the dust flow velocity are determined, and indicator foils and thin glasses are used to calculate the specific weight of the dust. Dependences of the specific weight of particles on their relative velocity are constructed. Effects of roughness and phase state of the substance after a shock-wave load on the possibilities to determine the velocity of the free surface and the specific weight of discharged particles using indicator foils are analyzed. It is shown that, with given surface roughness, the specific weight of dust, discharged from the surface during lead melting under the action of a shock wave or load wave, is much larger than in a sample being in a solid state.

Particles are discharged from surfaces of materials under a shock-wave load. Experimental results on determining the minimal values of a specific weight of particles with which their velocity can be detected using a heterodyne interferometer [photon Doppler velocimetry (PDV) method] are presented. An effect of multiple frequency shift of a Doppler signal in the case of laser radiation being reflected from surfaces of materials and a semitransparent layer of dust particles is described.

We report results from an experiment on Pb that we explosively shock loaded to PSL≈32\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$P_{SL} \approx 32$$\end{document}- and 43-GPa, in a single experiment. These PSL\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$P_{SL}$$\end{document} caused the Pb sample to isentropically release to either a liquid or mixed solid–liquid phase post-shock. The post-shock sample damage and dynamics were diagnosed with proton radiography, which gave quantitative damage data within three distinct regions. The first region is the particle (ejecta) cloud, where we observed that total areal mass ejected from the shocked Pb surface is in-dependent of the peak PSL\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$P_{SL}$$\end{document} for unsupported (Taylor wave) shockwave loading. The second region, which exhibits spall and cavitation, distends and disperses as the shocked coupon self-similarly expands subsequent to the shockwave impulse and the release into tension. The third region includes undamaged, full density Pb sample. We report quantitative observations from all three regions, and we used the data to evaluate and validate damage and ejecta models, which satisfactorily describe the observed experimental dynamics.

We report results from an experiment on Pb that we explosively shock loaded to \(P_{SL} \approx 32\)- and 43-GPa, in a single experiment. These \(P_{SL}\) caused the Pb sample to isentropically release to either a liquid or mixed solid–liquid phase post-shock. The post-shock sample damage and dynamics were diagnosed with proton radiography, which gave quantitative damage data within three distinct regions. The first region is the particle (ejecta) cloud, where we observed that total areal mass ejected from the shocked Pb surface is in-dependent of the peak \(P_{SL}\) for unsupported (Taylor wave) shockwave loading. The second region, which exhibits spall and cavitation, distends and disperses as the shocked coupon self-similarly expands subsequent to the shockwave impulse and the release into tension. The third region includes undamaged, full density Pb sample. We report quantitative observations from all three regions, and we used the data to evaluate and validate damage and ejecta models, which satisfactorily describe the observed experimental dynamics.

We report results from an experiment on Pb that we explosively shock loaded to P_SL≈ 32 - and 43-GPa, in a single experiment. These P_SL caused the Pb sample to isentropically release to either a liquid or mixed solid–liquid phase post-shock. The post-shock sample damage and dynamics were diagnosed with proton radiography, which gave quantitative damage data within three distinct regions. The first region is the particle (ejecta) cloud, where we observed that total areal mass ejected from the shocked Pb surface is in-dependent of the peak P_SL for unsupported (Taylor wave) shockwave loading. The second region, which exhibits spall and cavitation, distends and disperses as the shocked coupon self-similarly expands subsequent to the shockwave impulse and the release into tension. The third region includes undamaged, full density Pb sample. We report quantitative observations from all three regions, and we used the data to evaluate and validate damage and ejecta models, which satisfactorily describe the observed experimental dynamics.

Experimental results on the study of spallation and cavitation from solid (Cu and Pb) and liquefied Pb are presented. Pb ejecta transporting in air is also studied with a multi-probe laser interferometry method that is applied to detect and quantify the particle cloud velocity and surface fragmentation. The laser diagnostic is designed to probe ejecta velocity- and dispersion-profiles within ejecta fragment clouds, and spallation structures.

The presence and behavior of a gas–metal interfacial layer at the free surface of shock-wave driven flying vehicles in gases of various compositions and densities has not been sufficiently studied so far. We present new comparative data on “dusting” from the free surface of lead into vacuum and gas as dependent on the surface roughness, pressure amplitude at the shock-wave front, and phase state of the material. Methods of estimating the mass flux of ejected particles in the presence of a gas medium at the free metal surface are proposed.

In view of the possible effect of contamination of a plasma by metal particles on the operation of a number of facilities or on the detection of the motion of liners by Doppler methods, a particular attention has been recently focused on the problem of the ejection of particles from the shock-loaded free surface of a sample or on the “dusting” problem. Most information concerns the dusting source associated with the roughness of the surface, manufacturing technology, and the defectiveness and aging of a material. Factors affecting this process such as the profile and amplitude of the pressure on the front of the shock wave arriving at the free surface of the sample, the presence of the gas in front of the free surface, and the pressure in this gas are less studied.

The results of experiments on studying spallation and the ejection of particles from the surfaces of copper and lead samples are presented. A laser interferometry method is used to detect the particle cloud velocity and the multiple spallation parameters. Angular detectors are used to detect the depth profile of the particle cloud velocity dispersion and the structure of metal spallation.

This paper presents the results of experimental studies of the cavitation breakdown of liquids in a wide range of shock-wave loading. The free surface velocity of liquids and the velocity spectrum of the cloud of particles and jets were measured using a laser heterodyne interferometer (photon Doppler velocimetry), and their size was determined. The spall strength of distilled water was determined.

The paper presents the Gamma-4 four-module electrophysical facility project developed for radiation physics research. For this facility, we have developed and tested a typical module which, with a matched load, generates an electrical pulse with voltage and current amplitudes of up to 2 MV and 750 kA, respectively, and with a half-height duration of 60 ns. 700 shots were performed which conformed the operating parameters and reliability of the module. Layouts of the facility for the modes of synchronous (with accuracy of ±3 ns) operation of the modules with vacuum electron diodes and with a current summator to generate soft x-ray pulses have been developed.

A synchronization system for the Gamma-4 four-module electrophysical facility has been developed. It has been shown that the synchronization system should provide triggering (with precision not worse than ±3 ns) of the high-voltage gas-filled trigatron-type switches of the facility modules (144 spark gaps with an operating voltage of 1 MV), the pre-pulse switches of the modules (24 spark gaps with an operating voltage of 3 MV) and eight Arkad’ev-Marx generators (40 spark gaps with an operating voltage of 100 kV).