Shock Wave and High Pressure Phenomena – serie

For a brief period during the latter part of World War II, Nevill F. Mott led a theoretical group at Fort Halstead in the United Kingdom that tackled scientific issues related to pressing war-time concerns. Among later awards and honors, Mott was knighted and a recipient of the Nobel Prize. While at Fort Halstead, he undertook an effort to theoretically describe the statistical fragmentation of munitions subjected to intense explosive loading. Mott`s original internal reports contain seminal theoretical concepts on the physics and statistics of dynamic fracture and fragmentation, which have provided the inspiration for numerous later modeling efforts and engineering formulae. Some of his most forward-looking thoughts on the micromechanical and molecular aspects of fracture are included in these publications. The present book surveys the theoretical analysis put forth by Mott with particular focus on his efforts to characterize the size and distribution of fragments resulting from a dynamic fragmentation event. Copies of the original internal reports of Mott and his co-workers are included. The book also pursues additional theoretical analysis with the intent of delving further into the physical ideas and unfinished analysis implicit in Mott`s original studies. This book will be of interest to all scientists and engineers concerned with the dynamic fracture and fragmentation of solid bodies subject to intense transient loads imparted by explosive detonation and high-velocity impact from both the historical and modern perspective.

One of the main goals of investigations of shock-wave phenomena in condensed matter is to develop methods for predicting effects of explosions, high-velocity collisions, and other kinds of intense dynamic loading of materials and structures. Based on the results of international research conducted over the past 30 years, this book is addressed not only to experts in shock-wave physics, but also to interested representatives from adjacent fields of activity and to students who seek an introduction to the current issues. With that goal in mind, the book opens with a brief account of the theoretical background and a short description of experimental techniques. The authors then progress to a systematic treatment of special topics, some of which have not been fully addressed in the literature to date.

Presenting some of the most recent results of Russian research into shock compression, as well as historical overviews of the Russian research programs into shock compression, this volume will provide Western researchers with many novel ideas and points of view. The chapters in this volume are written by leading Russian specialists various fields of high-pressure physics and form accounts of the main researches on the behavior of matter under shock-wave interaction. The experimental portions contain results of studies of shock compression of metals to high and ultra-high pressure, shock initiation of polymorphic transformations, strength, fracture and fragmentation under shock compression, and detonation of condensed explosives. There are also chapters on theoretical investigations of shock-wave compression and plasma states in regimes of high-pressure and high- temperature. The topics of the book are of interest to scientists and engineers concerned with questions of material behavior under impulsive loading and to the equation of state of matter. Application is to questions of high-speed impact, inner composition of planets, verification of model representations of material behavior under extreme 1oading conditions, syntheses of new materials, development of new technologies for material processing, etc. Russian research differs from much of the Western work in that it has traditionally been wider-ranging and more directed to extremes of response than to precise characterization of specific materials and effects. Western scientists could expect to benefit from the perspective gained from close knowledge of the Russian work.

In the 1950s explosives began to be used to generate ultrahigh pressures in condensed substances in order to modify their properties and structure. Notwithstanding the short duration of an explosion, its energy proved to be high enough to perform physical-chemical transformations of substances, and the new method gained wide industrial applications. It has both advan­ tages and drawbacks in comparison with the traditional method of static compression. The latter method, notorious for its cumbersome and expensive machin­ ery, allows one to maintain high pressure as long as one pleases and to regu­ late the temperature of the sample arbitrarily. But, the pressure available is rather limited and for any increase of this limit one has to pay by the progres­ sive shrinking of the working volume of a press. The dynamic method has the advantages of low cost and practically no restrictions of magnitude of pressure and the size of a processed sample, but the temperature in a compressed body is no longer controlled by an experi­ mentor. Rather, it is firmly dictated by the level of loading, according to the equation of state. Hence, it is difficult to recover metastable products and impossible to prepare solids with a low concentration of defects as the dura­ tion of explosion is too short for their elimination.

It seems that there is no book that treats the measurement of the physical pa­ rameters of explosives as its only subject, although limited information is avail­ able in a number of books. Therefore, I have tried to bridge this gap in the lit­ erature with this book. A large number of various physical parameters have to be determined ex­ perimentally in order to test or characterise an explosive. Various physical principles have been applied for such measurements. Accordingly, a large number of different experimental methods exist, as well as various testing appa­ ratuses and procedures. On the other hand, great progress has been made recently in the study of detonation phenomena. New measuring techniques can assess extremely short processes to below nanoseconds scale. They make it possible to determine im­ portant parameters in detonation physics. I have made a great attempt to cover the available literature data on the subject. Because it would be a highly demanding task to include in a single volume all the methods that are in use by various testing agencies, I have tried to give primarily the principles for determination of individual physical pa­ rameters of explosives by different measuring methods as well as data treatment procedures.

This monograph deals with the behavior of essentially nonlinear heterogeneous materials in processes occurring under intense dynamic loading, where microstructural effects play the main role. This book is not an introduction to the dynamic behavior of materials, and general information available in other books is not included. The material herein is presented in a form I hope will make it useful not only for researchers working in related areas, but also for graduate students. I used it successfully to teach a course on the dynamic behavior of materials at the University of California, San Diego. Another course well suited to the topic may be nonlinear wave dynamics in solids, especially the part on strongly nonlinear waves. About 100 problems presented in the book at the end of each chapter will help the reader to develop a deeper understanding of the subject. I tried to follow a few rules in writing this book: (1) To focus on strongly nonlinear phenomena where there is no small parameter with respect to the amplitude of disturbance, including solitons, shock waves, and localized shear. (2) To take into account phenomena sensitive to materials structure, where typical space scale of material parameters (particle size, cell size) are presented in the models or are variable in experimental research.

Shock waves produce a wide variety of physical, chemical, mineralogical, and other effects in materials through which they pass. Since the beginning of civili­ zation, shock phenomena have been subjects of continuing interest, speculation, and enquiry. The interdisciplinary aspects of investigations of shock phenomena are especially noteworthy, and these investigations have been pursued by scien­ tists and engineers from a broad range of disciplines. Among the more novel and interesting investigations are those motivated by problems that arise in the Earth and planetary sciences. Such events as meteorite impacts produce the obvious cratering effects seen on the planets and their sat­ ellites. More subtle effects become apparent upon chemical and petrographic examination of the shock-compressed solid material. Shock waves are also prevalent in the larger universe, and have played a prominent role in shaping the solar system as we know it. The material in interstellar gas and dust clouds, comets, etc. , is processed by shock waves, producing important chemical effects, including formation of complex organic molecules. The process of accretion of planets involves impacts of dust particles at relative velocities ranging from a fraction of a millimeter per second to impacts of larger bodies at velocities as great as several tens of kilometers per second. The resulting shock waves cause both chemical and physical changes that are manifest in the bodies involved.

Shock-induced dynamic fracture of solids is of practical importance in many areas of materials science, chemical physics, engineering, and geophysics. This book, by an international roster of authors, comprises a systematic account of the current state of research in the field, integrating the large amount of work done in the former Soviet Union with the work done in the West. Topics covered include: Wave propagation, experimental techniques and measurements, spallation of materials of different classes (metals, ceramics, glasses, polymers), constitutive models of fracture processes, and computer simulations.

Both experimental and theoretical investigations make it clear that mesoscale materials, that is, materials at scales intermediate between atomic and bulk matter, do not always behave in ways predicted by conventional theories of shock compression. At these scales, shock waves interact with local material properties and microstructure to produce a hierarchy of dissipative structures such as inelastic deformation fields, randomly distributed lattice defects, and residual stresses. A macroscopically steady planar shock wave is neither plane nor steady at the mesoscale. The chapters in this book examine the assumptions underlying our understanding of shock phenomena and present new measurements, calculations, and theories that challenge these assumptions. They address such questions as: - What are the experimental data on mesoscale effects of shocks, and what are the implications? - Can one formulate new mesoscale theories of shock dynamics? - How would new mesoscale theories affect our understanding of shock-induced phase transitions or fracture? - What new computational models will be needed for investigating mesoscale shocks?

This is a broad-based text on the fundamentals of explosive behavior and the application of explosives in civil engineering, industrial processes, aerospace applications, and military uses.

This book presents a set of basic understandings of the behavior and response of solids to propagating shock waves. The propagation of shock waves in a solid body is accompanied by large compressions, decompression, and shear. Thus, the shear strength of solids and any inelastic response due to shock­ wave propagation is of the utmost importance. Furthermore, shock compres­ sion of solids is always accompanied by heating, and the rise of local tempera­ ture which may be due to both compression and dissipation. For many solids, under a certain range of impact pressures, a two-wave structure arises such that the first wave, called the elastic prescursor, travels with the speed of sound; and the second wave, called a plastic shock wave, travels at a slower speed. Shock-wave loading of solids is normally accomplished by either projectile impact, such as produced by guns or by explosives. The shock heating and compression of solids covers a wide range of temperatures and densities. For example, the temperature may be as high as a few electron volts (1 eV = 11,500 K) for very strong shocks and the densification may be as high as four times the normal density.

The field of shock compression science has a long and rich history involving contributions of mathematicians, physicists and engineers over approximately two hundred years. The middle of the nineteenth century was an especially ac­ tive period with the contributions of Riemann, Rankine and Hugoniot, among others. The middle of the twentieth century saw another increase in activity re­ lated to shock compression of condensed matter as a result of military applica­ tions. It was also recognized that shock compression provided a means of sub­ jecting solids and liquids to extreme states of temperature and pressure difficult to achieve by static means. It has thus become an academic study in its own right. The principal modem contributions to this science were summarized in the landmark paper by Rice, McQueen and Walsh [Solid State Physics, Vol. 6, pp. 1-63, 1958]. As this field has continued to mature, interest has increased in tracing the early papers that have served as the foundations of the field. Cheret [Shock Compression of Condensed Matter - 1989, Elsevier Sci. Pub. B. V. , pp 11-19, 1990) has contributed to this literature with his review of the life of Hugoniot on the one-hundredth anniversary of the publication of Hugoniot's classic paper on the propagation of discontinuous waves in gases. This contribution prompted additional historical investigation involving the precursors to Hugoniot.

It is known that the Chapman-Jouguet theory of detonation is based on the assumption of an instantaneous and complete transformation of explosives into detonation products in the wave front. Therefore, one should not expect from the theory any interpretations of the detonation limits, such as shock initiation of det­ onation and kinetic instability and propagation (failure diameter). The Zeldovich-Von Neuman-Doring (ZND) theory of detonation appeared, in fact, as a response to the need for a theory capable of interpreting such limits, and the ZND detonation theory gave qualitative interpretations to the detonation limits. These interpretations were based essentially on the theoretical notion that the mechanism of explosives transformation at detonation is a combustion of a layer of finite thickness of shock-compressed explosive behind the wave shock front with the velocity of the front. However, some experimental findings turned out to be inconsistent with the the­ ory. A very small change of homogeneous (liquid) explosives detonation velocity with explosive charge diameter near the rather sizable failure diameter is one of the findings. The elucidation of the nature of this finding has led to the discovery of a new phenomenon. This phenomenon has come to be known as the breakdown (BD) of the explosive self-ignition behind the front of shock waves under the effect of rarefaction waves.

Devices that convert explosive energy into electromagnetic energy are often called Flux Compression Generators (FCGs) in the United States, whereas the term Magnetocumulative Generators (MCGs) is more com­ monly used in Russia. Since the Russian literature is accessed more heavily in this book, the latter term is used here. In any event, the basic process involves using explosives to force an initial magnetic flux into a region of smaller inductance in such a manner that loss of flux is minimized. In the event that no flux is lost, the magnetic energy associated with the flux, inversely proportional to the inductance, must increase. Flux loss is min­ imized by confining it with good conductors which, in turn, are driven rapidly by the explosive to reduce the system inductance. The magnetic energy is increased by the work the conductors do as they are forcibly moved against the magnetic field, the energy, in turn, being supplied by the explosive driving them. As the reader may infer, there are different kinds of generators, some of which might be difficult to recognize as MCGs. Nonetheless, they all possess the features outlined above. Explosives have some unique features as energy sources. They have very high available energy densities; they release energy rapidly, or at high power; they can develop very high pressures.

One of the main goals of investigations of shock-wave phenomena in condensed matter is to develop methods for predicting effects of explosions, high-velocity collisions, and other kinds of intense dynamic loading of materials and structures. Based on the results of international research conducted over the past 30 years, this book is addressed not only to experts in shock-wave physics, but also to interested representatives from adjacent fields of activity and to students who seek an introduction to the current issues. With that goal in mind, the book opens with a brief account of the theoretical background and a short description of experimental techniques. The authors then progress to a systematic treatment of special topics, some of which have not been fully addressed in the literature to date.

Presenting some of the most recent results of Russian research into shock compression, as well as historical overviews of the Russian research programs into shock compression, this volume will provide Western researchers with many novel ideas and points of view. The chapters in this volume are written by leading Russian specialists various fields of high-pressure physics and form accounts of the main researches on the behavior of matter under shock-wave interaction. The experimental portions contain results of studies of shock compression of metals to high and ultra-high pressure, shock initiation of polymorphic transformations, strength, fracture and fragmentation under shock compression, and detonation of condensed explosives. There are also chapters on theoretical investigations of shock-wave compression and plasma states in regimes of high-pressure and high- temperature. The topics of the book are of interest to scientists and engineers concerned with questions of material behavior under impulsive loading and to the equation of state of matter. Application is to questions of high-speed impact, inner composition of planets, verification of model representations of material behavior under extreme 1oading conditions, syntheses of new materials, development of new technologies for material processing, etc. Russian research differs from much of the Western work in that it has traditionally been wider-ranging and more directed to extremes of response than to precise characterization of specific materials and effects. Western scientists could expect to benefit from the perspective gained from close knowledge of the Russian work.

In the 1950s explosives began to be used to generate ultrahigh pressures in condensed substances in order to modify their properties and structure. Notwithstanding the short duration of an explosion, its energy proved to be high enough to perform physical-chemical transformations of substances, and the new method gained wide industrial applications. It has both advan­ tages and drawbacks in comparison with the traditional method of static compression. The latter method, notorious for its cumbersome and expensive machin­ ery, allows one to maintain high pressure as long as one pleases and to regu­ late the temperature of the sample arbitrarily. But, the pressure available is rather limited and for any increase of this limit one has to pay by the progres­ sive shrinking of the working volume of a press. The dynamic method has the advantages of low cost and practically no restrictions of magnitude of pressure and the size of a processed sample, but the temperature in a compressed body is no longer controlled by an experi­ mentor. Rather, it is firmly dictated by the level of loading, according to the equation of state. Hence, it is difficult to recover metastable products and impossible to prepare solids with a low concentration of defects as the dura­ tion of explosion is too short for their elimination.

This monograph deals with the behavior of essentially nonlinear heterogeneous materials in processes occurring under intense dynamic loading, where microstructural effects play the main role. This book is not an introduction to the dynamic behavior of materials, and general information available in other books is not included. The material herein is presented in a form I hope will make it useful not only for researchers working in related areas, but also for graduate students. I used it successfully to teach a course on the dynamic behavior of materials at the University of California, San Diego. Another course well suited to the topic may be nonlinear wave dynamics in solids, especially the part on strongly nonlinear waves. About 100 problems presented in the book at the end of each chapter will help the reader to develop a deeper understanding of the subject. I tried to follow a few rules in writing this book: (1) To focus on strongly nonlinear phenomena where there is no small parameter with respect to the amplitude of disturbance, including solitons, shock waves, and localized shear. (2) To take into account phenomena sensitive to materials structure, where typical space scale of material parameters (particle size, cell size) are presented in the models or are variable in experimental research.

Shock-induced dynamic fracture of solids is of practical importance in many areas of materials science, chemical physics, engineering, and geophysics. This book, by an international roster of authors, comprises a systematic account of the current state of research in the field, integrating the large amount of work done in the former Soviet Union with the work done in the West. Topics covered include: Wave propagation, experimental techniques and measurements, spallation of materials of different classes (metals, ceramics, glasses, polymers), constitutive models of fracture processes, and computer simulations.

Shock waves produce a wide variety of physical, chemical, mineralogical, and other effects in materials through which they pass. Since the beginning of civili­ zation, shock phenomena have been subjects of continuing interest, speculation, and enquiry. The interdisciplinary aspects of investigations of shock phenomena are especially noteworthy, and these investigations have been pursued by scien­ tists and engineers from a broad range of disciplines. Among the more novel and interesting investigations are those motivated by problems that arise in the Earth and planetary sciences. Such events as meteorite impacts produce the obvious cratering effects seen on the planets and their sat­ ellites. More subtle effects become apparent upon chemical and petrographic examination of the shock-compressed solid material. Shock waves are also prevalent in the larger universe, and have played a prominent role in shaping the solar system as we know it. The material in interstellar gas and dust clouds, comets, etc. , is processed by shock waves, producing important chemical effects, including formation of complex organic molecules. The process of accretion of planets involves impacts of dust particles at relative velocities ranging from a fraction of a millimeter per second to impacts of larger bodies at velocities as great as several tens of kilometers per second. The resulting shock waves cause both chemical and physical changes that are manifest in the bodies involved.

Both experimental and theoretical investigations make it clear that mesoscale materials, that is, materials at scales intermediate between atomic and bulk matter, do not always behave in ways predicted by conventional theories of shock compression. At these scales, shock waves interact with local material properties and microstructure to produce a hierarchy of dissipative structures such as inelastic deformation fields, randomly distributed lattice defects, and residual stresses. A macroscopically steady planar shock wave is neither plane nor steady at the mesoscale. The chapters in this book examine the assumptions underlying our understanding of shock phenomena and present new measurements, calculations, and theories that challenge these assumptions. They address such questions as: - What are the experimental data on mesoscale effects of shocks, and what are the implications? - Can one formulate new mesoscale theories of shock dynamics? - How would new mesoscale theories affect our understanding of shock-induced phase transitions or fracture? - What new computational models will be needed for investigating mesoscale shocks?

It is known that the Chapman-Jouguet theory of detonation is based on the assumption of an instantaneous and complete transformation of explosives into detonation products in the wave front. Therefore, one should not expect from the theory any interpretations of the detonation limits, such as shock initiation of det­ onation and kinetic instability and propagation (failure diameter). The Zeldovich-Von Neuman-Doring (ZND) theory of detonation appeared, in fact, as a response to the need for a theory capable of interpreting such limits, and the ZND detonation theory gave qualitative interpretations to the detonation limits. These interpretations were based essentially on the theoretical notion that the mechanism of explosives transformation at detonation is a combustion of a layer of finite thickness of shock-compressed explosive behind the wave shock front with the velocity of the front. However, some experimental findings turned out to be inconsistent with the the­ ory. A very small change of homogeneous (liquid) explosives detonation velocity with explosive charge diameter near the rather sizable failure diameter is one of the findings. The elucidation of the nature of this finding has led to the discovery of a new phenomenon. This phenomenon has come to be known as the breakdown (BD) of the explosive self-ignition behind the front of shock waves under the effect of rarefaction waves.

It seems that there is no book that treats the measurement of the physical pa­ rameters of explosives as its only subject, although limited information is avail­ able in a number of books. Therefore, I have tried to bridge this gap in the lit­ erature with this book. A large number of various physical parameters have to be determined ex­ perimentally in order to test or characterise an explosive. Various physical principles have been applied for such measurements. Accordingly, a large number of different experimental methods exist, as well as various testing appa­ ratuses and procedures. On the other hand, great progress has been made recently in the study of detonation phenomena. New measuring techniques can assess extremely short processes to below nanoseconds scale. They make it possible to determine im­ portant parameters in detonation physics. I have made a great attempt to cover the available literature data on the subject. Because it would be a highly demanding task to include in a single volume all the methods that are in use by various testing agencies, I have tried to give primarily the principles for determination of individual physical pa­ rameters of explosives by different measuring methods as well as data treatment procedures.

This book presents a set of basic understandings of the behavior and response of solids to propagating shock waves. The propagation of shock waves in a solid body is accompanied by large compressions, decompression, and shear. Thus, the shear strength of solids and any inelastic response due to shock­ wave propagation is of the utmost importance. Furthermore, shock compres­ sion of solids is always accompanied by heating, and the rise of local tempera­ ture which may be due to both compression and dissipation. For many solids, under a certain range of impact pressures, a two-wave structure arises such that the first wave, called the elastic prescursor, travels with the speed of sound; and the second wave, called a plastic shock wave, travels at a slower speed. Shock-wave loading of solids is normally accomplished by either projectile impact, such as produced by guns or by explosives. The shock heating and compression of solids covers a wide range of temperatures and densities. For example, the temperature may be as high as a few electron volts (1 eV = 11,500 K) for very strong shocks and the densification may be as high as four times the normal density.

Devices that convert explosive energy into electromagnetic energy are often called Flux Compression Generators (FCGs) in the United States, whereas the term Magnetocumulative Generators (MCGs) is more com­ monly used in Russia. Since the Russian literature is accessed more heavily in this book, the latter term is used here. In any event, the basic process involves using explosives to force an initial magnetic flux into a region of smaller inductance in such a manner that loss of flux is minimized. In the event that no flux is lost, the magnetic energy associated with the flux, inversely proportional to the inductance, must increase. Flux loss is min­ imized by confining it with good conductors which, in turn, are driven rapidly by the explosive to reduce the system inductance. The magnetic energy is increased by the work the conductors do as they are forcibly moved against the magnetic field, the energy, in turn, being supplied by the explosive driving them. As the reader may infer, there are different kinds of generators, some of which might be difficult to recognize as MCGs. Nonetheless, they all possess the features outlined above. Explosives have some unique features as energy sources. They have very high available energy densities; they release energy rapidly, or at high power; they can develop very high pressures.

Developments in experimental methods are providing an increasingly detailed understanding of shock compression phenomena on the bulk, intermediate, and molecular scales. This third volume in a series of reviews of the curent state of knowledge covers several diverse areas. The first group of chapters addresses fundamental physical and chemical aspects of the response of condensed matter to shock comression: equations of state, molecular-dynamic analysis, deformation of materials, spectroscopic methods. Two further chapters focus on a particular group of materials: ceramics. Another chapter discusses shock-induced reaction of condensed-phase explosives. And a final pair of chapters considers shock phenomena at low stresses from the point of view of continuum mechanics.

The field of shock compression science has a long and rich history involving contributions of mathematicians, physicists and engineers over approximately two hundred years. The middle of the nineteenth century was an especially ac­ tive period with the contributions of Riemann, Rankine and Hugoniot, among others. The middle of the twentieth century saw another increase in activity re­ lated to shock compression of condensed matter as a result of military applica­ tions. It was also recognized that shock compression provided a means of sub­ jecting solids and liquids to extreme states of temperature and pressure difficult to achieve by static means. It has thus become an academic study in its own right. The principal modem contributions to this science were summarized in the landmark paper by Rice, McQueen and Walsh [Solid State Physics, Vol. 6, pp. 1-63, 1958]. As this field has continued to mature, interest has increased in tracing the early papers that have served as the foundations of the field. Cheret [Shock Compression of Condensed Matter - 1989, Elsevier Sci. Pub. B. V. , pp 11-19, 1990) has contributed to this literature with his review of the life of Hugoniot on the one-hundredth anniversary of the publication of Hugoniot's classic paper on the propagation of discontinuous waves in gases. This contribution prompted additional historical investigation involving the precursors to Hugoniot.

This volume concerns the fracture and fragmentation of solid materials that occurs when they are subjected to extremes of stress applied at the highest possible rates. The plan for the volume is to address experimental, theoretical, and com­ putational aspects of high-rate dynamic fracture and fragmentation, with emphasis on recent work. We begin with several chapters in which the emphasis falls on experimental methods and observations. These chapters address both macroscopic responses and the microscopic cause of these re­ sponses. This is followed by several chapters emphasizing modeling-the physical explanation and mathematical representation of the observations. Some of the models are deterministic, while others focus on the stochastic aspects of the observations. Often, the ov\!rall objective of investigation of dynamic fracture and fragmentation phenomena is provision of a means for predicting the entire course of an event that begins with a stimulus such as an impact and proceeds through a complicated deformation and fracture pro­ cess that results in disintegration of the body and formation of a rapidly expanding cloud of debris fragments. Analysis of this event usually involves development of a continuum theory and computer code that captures the experimental observations by incorporating models of the important pheno­ mena into a comprehensive description of the deformation and fracture pro­ cess. It is to this task that the work of the last few chapters is devoted.

Since the 1950s shock compression research contributed greatly to scientific knowledge and industrial technology. As a result, for example, our understanding of meteorite impacts has substantially improved, and shock processes have become standard industrial methods in materials synthesis and processing. Investigations of shock-compressed matter involve physics,electrical engineering, solid mechanics, metallurgy, geophysics and materials science. The description of shock-compressed matter presented here, which is derived from physical and chemical observations, differs significantly from the classical descriptions derived from strictly mechanical characteristics. This volume, with over 900 references, provides an introduction for scientists and engineers interested in the present state of shock compression science.