RADIATION ACOUSTICS RADIATION ACOUSTICS Leonid M. Lyamshev CRC PR ESS Boca Raton London New York Washington, D.C. Library of Congress Cataloging-in-Publication Data Lyamshev, Leonid M. Radiation acoustics / Leonid M. Lyamshev. p. ; cm. Includes bibliographical references and index. ISBN 0-415-30999-9 (alk. paper) 1. Sound-waves. 2. Sound—Transmission. 3. Radiation sources. I. Title. [DNLM: 1. Radiation. 2. Acoustics. 3. Radiation Effects. 4. Thermodynamics. WN 100 L981r 2004] QC243.L93 2004 534—dc22 2003070031 This book contains information obtained from authentic and highly regarded sources. Reprinted material is quoted with permission, and sources are indicated. A wide variety of references are listed. Reasonable efforts have been made to publish reliable data and information, but the author and the publisher cannot assume responsibility for the validity of all materials or for the consequences of their use. 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Visit the CRC Press Web site at www.crcpress.com © 2004 by CRC Press LLC No claim to original U.S. Government works International Standard Book Number 0-415-30999-9 Library of Congress Card Number 2003070031 Printed in the United States of America 1 2 3 4 5 6 7 8 9 0 Printed on acid-free paper FOREWORD Radiation acoustics is a new field of research developing at the interface of acoustics, nuclear physics, high energy physics, and the physics of elementary particles. It is founded upon studies and applications of radiation-acoustic effects arising in the process of interaction of penetrating radiation with matter. The thermoradiation mechanism has been the best studied among the mechanisms of sound excitation by penetrating radiation in condensed media. According to this mechanism, sound generation is caused by thermal expansion of a medium, and the acoustic field can be described as a rule within the framework of linear theory. The book considers mainly the processes of thermoradiation sound excitation in the case of continuous (modulated) and pulsed action of penetrating radiation on a substance. Basic laws of formation of acoustic signals are established and the bonds between the characteristics of these signals, radiation parameters, and thermodynamic, radiation, and acoustic properties of substances are revealed. The efficiency and optimal conditions of thermoradiation sound generation are considered. The particular features of sound generation by a particle beam moving along the surface of a liquid or solid at subsonic and supersonic velocities and an arbitrary form of modulation of radiation intensity in the beam are described. The possibility is discussed of the creation of virtual radiation-acoustic sources of sound in a wide frequency range (from sound to hypersound frequencies) with controlled parameters in liquids or solids. We consider the particular features of thermoradiation generation of sound by single particles. Experimental results on sound excitation by beams of photons (laser radiation), electrons, protons, heavy ions, X-rays, and gamma-quanta are given. Some other mechanisms of sound generation by single particles in the process of their absorption in a medium are considered apart from the thermoradiation mechanism, i.e., the mechanisms of microshock waves and the bubble, dynamic, Cherenkov, and striction mechanisms. Applications of radiation acoustics are discussed. We have not tried to go into the details of many of them. Our purpose is to demonstrate the prospects of application of radiation acoustics to various fields from microelectronics (radiation-acoustic microscopy) to geophysics (neutrino- acoustic sounding of the Earth), and astrophysics (detection of cosmic neutrino and muons of super-high energy by huge acoustic detectors in the ocean). We have not tried to review all papers on radiation acoustics. On the contrary, we have quite deliberately not included in the book the results of studies of nonlinear radiation-acoustic phenomena arising in the process of interaction of powerful radiation beams with matter. Although the role of nonlinear effects in future radiation-acoustic technologies will undoubtedly be essential (targeted action on physical, mechanical and chemical structure of substances, radiation-acoustic destruction of materials, etc.), investigation of these effects still continues. The book may be useful not only to acousticians but also researchers and technicians specializing in adjacent and other fields as well as postgraduates and university students. I am very grateful to G. A. Askar’yan, F. V. Bunkin, and V. I. Il’ichev for many useful remarks on the manuscript. L. M. Bolotova, M. G. Lisovskaya, and B. I. Chelnokov helped me greatly in the preparation of the manuscript for publication. I am deeply grateful to them. L. M. Lyamshev CONTENTS INTRODUCTION 1 Chapter 1. PENETRATING RADIATION: GENERAL INFORMATION 7 1. Elementary particles: Fundamental laws of the microscopic world 7 2. Absorption of penetrating radiation in a condensed medium 13 Chapter 2. BASIC MECHANISMS OF SOUND GENERATION BY PENETRATING RADIATION IN CONDENSED MEDIA 23 1. Mechanisms connected with heat release 23 2. Thermoradiation generation of sound 24 3. Initiation of microshock waves 28 4. Bubble mechanism 30 5. The Cherenkov mechanism 31 6. Striction mechanism of sound generation 33 7. Sound generation in the process of pulsed radiolysis 35 8. Dynamic mechanism 35 9. Other mechanisms of sound generation 38 Chapter 3. THERMORADIATION EXCITATION OF SOUND IN A HOMOGENEOUS LIQUID 39 1. Equation of thermoradiation generation of sound 39 2. Reciprocity theorem in acoustics – Solution technique for boundary problems 42 3. Excitation of monochromatic sound in a liquid half-space with a free surface – The case of undisturbed surface 47 4. A liquid half-space with large-scale roughness of boundary 52 5. The case of small unevenness 61 6. Efficiency of thermoradiation excitation of sound in a liquid – Some estimates 72 Chapter 4. THERMORADIATION EXCITATION OF SOUND IN AN INHOMOGENEOUS MEDIUM 75 1. Sound excitation in a liquid half-space in the presence of a layer of another liquid at its boundary 75 2. Generation of sound in a liquid adjoining a solid layer 88 3. Liquid half-space with an inhomogeneous surface layer 96 Chapter 5. EXCITATION OF SOUND IN A LIQUID BY RADIATION PULSES 105 1. Sound generation in a liquid by rectangular pulses of radiation 106 2. A liquid with rough surface 113 3. Radiation pulses of arbitrary shape 116 4. Near wave field of thermoradiation pulsed source of sound 124 5. Sound generation in a liquid with gas bubbles 130 Chapter 6. GENERATION OF SOUND IN SOLIDS BY INTENSITY-MODULATED PENETRATING RADIATION 137 1. Basic equations 137 2. Boundary conditions 139 3. Method for solution of boundary problems 141 4. Thermoradiation generation of sound in a solid half-space with a free boundary 147 5. Particular features of excitation of Rayleigh waves 151 6. Solid half-space with a liquid layer at its surface 156 7. Efficiency of thermoradiation generation of sound 160 8. Influence of particular features of absorption of penetrating radiation on sound generation 164