The discrete sources method is an efficient and powerful tool for solving a large class of boundary-value problems in scattering theory. A variety of numerical methods for discrete sources now exist. In this book, the authors unify these formulations in the context of the so-called discrete sources method. Comprehensive presentation of the discrete sources method Original theory - an extension of the conventional null-field method using discrete sources Practical examples that demonstrate the efficiency and flexibility of elaborated methods (scattering by particles with high aspect ratio, rough particles, nonaxisymmetric particles, multiple scattering) List of discrete sources programmes available via the Internet

This book gives a detailed overview of the theory of electromagnetic wave scattering on single, homogeneous, but nonspherical particles. Beside the systematically developed Green’s function formalism of the first edition this second and enlarged edition contains additional material regarding group theoretical considerations for nonspherical particles with boundary symmetries, an iterative T-matrix scheme for approximate solutions, and two additional but basic applications. Moreover, to demonstrate the advantages of the group theoretical approach and the iterative solution technique, the restriction to axisymmetric scatterers of the first edition was abandoned.

This self-contained and accessible book provides a thorough introduction to the basic physical and mathematical principles required in studying the scattering and absorption of light and other electromagnetic radiation by particles and particle groups. For the first time the theories of electromagnetic scattering, radiative transfer, and weak localization are combined into a unified, consistent branch of physical optics directly based on the Maxwell equations. A particular focus is given to key aspects such as time and ensemble averaging at different scales, ergodicity, and the physical nature of measurements afforded by actual photopolarimeters. Featuring over 120 end-of-chapter exercises, with hints and solutions provided, this clear, one-stop resource is ideal for self-study or classroom use, and will be invaluable to both graduate students and researchers in remote sensing, physical and biomedical optics, optical communications, optical particle characterization, atmospheric physics and astrophysics.

This book develops the theory of the null-field method (also called T-matrix method), covering almost all aspects and current applications. This book also incorporates FORTRAN programs and simulation results. Worked examples of the application of the FORTRAN programs show readers how to adapt or modify the programs for their specific application.

This fourth volume of Light Scattering Reviews is composed of three parts. The ?rstpartisconcernedwiththeoreticalandexperimentalstudiesofsinglelightsc- tering by small nonspherical particles. Light scattering by small particles such as, for instance, droplets in the terrestrial clouds is a well understood area of physical optics. On the other hand, exact theoretical calculations of light scattering p- terns for most of nonspherical and irregularly shaped particles can be performed only for the restricted values of the size parameter, which is proportional to the ratio of the characteristic size of the particle to the wavelength?. For the large nonspherical particles, approximations are used (e. g. , ray optics). The exact th- retical techniques such as the T-matrix method cannot be used for extremely large particles, such as those in ice clouds, because then the size parameter in the v- iblex=2?a/???,wherea is the characteristic size (radius for spheres), and the associated numerical codes become unstable and produce wrong answers. Yet another problem is due to the fact that particles in many turbid media (e. g. , dust clouds) cannot be characterized by a single shape. Often, refractive indices also vary. Because of problems with theoretical calculations, experimental (i. e. , la- ratory) investigations are important for the characterization and understanding of the optical properties of such types of particles. The ?rst paper in this volume, written by B. Gustafson, is aimed at the descr- tionofscaledanalogueexperimentsinelectromagneticscattering.

This book presents the Generalized Multipole Technique as a fast and powerful theoretical and computation tool to simulate light scattering by nonspherical particles. It also demonstrates the considerable potential of the method. In recent years, the concept has been applied in new fields, such as simulation of electron energy loss spectroscopy and has been used to extend other methods, like the null-field method, making it more widely applicable. The authors discuss particular implementations of the GMT methods, such as the Discrete Sources Method (DSM), Multiple Multipole Program (MMP), the Method of Auxiliary Sources (MAS), the Filamentary Current Method (FCM), the Method of Fictitious Sources (MFS) and the Null-Field Method with Discrete Sources (NFM-DS). The Generalized Multipole Technique is a surface-based method to find the solution of a boundary-value problem for a given differential equation by expanding the fields in terms of fundamental or other singular solutions of this equation. The amplitudes of these fundamental solutions are determined from the boundary condition at the particle surface. Electromagnetic and light scattering by particles or systems of particles has been the subject of intense research in various scientific and engineering fields, including astronomy, optics, meteorology, remote sensing, optical particle sizing and electromagnetics, which has led to the development of a large number of modelling methods based on the Generalized Multipole Technique for quantitative evaluation of electromagnetic scattering by particles of various shapes and compositions. The book describes these methods in detail.

Only satellite-based remote-sensing instruments generate the wealth of global data on the concentrations of atmospheric constituents that are necessary for long-term monitoring of the atmosphere. This set of courses and lectures sponsored by ICTP in Trieste focuses on remote sensing for atmospheric applications and inverse methods to assess atmospheric components, gases, aerosols and clouds. It addresses primarily graduate students and young researchers in the atmospheric sciences but will be useful for all those wishing to study various techniques for exploring the atmosphere by remote sensing. Contributions span topics such as on IGOS (Integrated Global Observing Strategy), electromagnetic scattering by non-spherical particles, forward-modelling requirements and the information content problem, Earth radiation, and aerosol monitoring by LIDAR.

In fluid mechanics, non-intrusive measurements are fundamental in order to improve knowledge of the behavior and main physical phenomena of flows in order to further validate codes. The principles and characteristics of the different techniques available in laser metrology are described in detail in this book. Velocity, temperature and concentration measurements by spectroscopic techniques based on light scattered by molecules are achieved by different techniques: laser-induced fluorescence, coherent anti-Stokes Raman scattering using lasers and parametric sources, and absorption spectroscopy by tunable laser diodes, which are generally better suited for high velocity flows. The size determination of particles by optical means, a technique mainly applied in two-phase flows, is the subject of another chapter, along with a description of the principles of light scattering. For each technique the basic principles are given, as well as optical devices and data processing. A final chapter reminds the reader of the main safety precautions to be taken when using powerful lasers.

Marine Acoustics: Direct and Inverse Problems presents current research trends in the field of underwater acoustic wave direct and inverse problems. It is the first to investigate inverse problems in an ocean environment, with heavy emphasis on the description and resolution of the forward scattering problem.

This monograph on multiple scattering of light by small particles is an ideal resource for science professionals, engineers, and graduate students.