Electromagnetic Scattering and Absorption" is the first advanced course on elastic electromagnetic scattering by arbitrary objects (usually called particles). As compared to the wavelength, the sizes of the objects can be small or large, or of the order of the wavelength. As to the shape of the objects, the main emphasis is on spherical particles and, subsequently, on the so-called Mie scattering. The optical properties of the objects are typically described by the refractive index. During the course, the student will become familiar with the concepts of electromagnetic scattering and will learn how to use existing computer codes in astronomical and atmospheric applications.
In the beginning, classical electromagnetics is reviewed, intrododucing the Maxwell equations. Then follows the necessary framework for the classical scattering theory with the definitions for the Stokes parameters and Mueller matrices, as well as for the 2 x 2 scattering amplitude matrix and the 4 x 4 scattering matrix.
During the first three weeks, an introduction is offered to homogeneous plane waves, Fresnel reflection and refraction on a planar interface, as well as Mie scattering. During the second three weeks, the Rayleigh approximation (sphere and spheroid), the Rayleigh-Gans approximation, and the effective media approximation are assessed. Finally, applications are introduced in astronomy and radar meteorology.
The project and the exercises on the course will concern ray optics, Mie scattering, comparison of Rayleigh and Mie scattering in terms of applicability range, basic polarisation variables from the Rayleigh spheroid, and effective media approximation (scattering from snowflakes or melting particles, for example).
Towards the end of the course, the student will learn about the free existing softwares for scattering by nonspherical particles, such as the Amsterdam Discrete-Dipole Approximation code ADDA and the Superposition T-Matrix Method code MSTM (Multiple-Sphere T-Matrix).
|Study materials and literature
K. Muinonen, Electromagnetic Scattering I, Lecture Notes, 2012 (latest draft)
C. F. Bohren & D. R. Huffman, Absorption and Scattering of Light by Small Particles, Wiley & Sons, 2010
J. D. Jackson, Classical Electrodynamics, Wiley & Sons, 1998
H. C. van de Hulst, Light Scattering by Small Particles, Wiley & Sons, 1957 (Dover, 1981)
M. I. Mishchenko, J. W. Hovenier, \& L. D. Travis, Light Scattering by Nonspherical Particles, Academic Press, 2000
M. I. Mishchenko, L. D. Travis & A. A. Lacis, Scattering, Absorption, and Emission of Light by Small Particles, Cambridge University Press, 2002
A. Doicu, Y. Eremin & T. Wriedt, Acoustic & Electromagnetic
Scattering Analysis Using Discrete Sources, Academic Press, 2000