Computational light scattering

Last modified by Antti Penttilä on 2025/02/04 07:09

Course page for Computational light scattering — Laskennallinen valonsironta

Advanced Course, 5 credits, PAP315, Autumn 2024, Period 1

Computational light scattering assesses elastic light scattering (electromagnetic scattering) by particles of arbitrary sizes, shapes, and optical properties. Particular attention is paid to advanced computational methods for both single and multiple scattering, that is, to methods for isolated particles and extended media of particles (cf. dust particles in cometary comae and particulate media on asteroids). Theoretical foundations are described for the physics of light scattering based on the Maxwell equations and for a number of computational methods. In single scattering, the methods include, for example, the volume integral equation, discrete-dipole approximation, T-matrix or transition matrix, and finite-difference time-domain methods. In multiple scattering, the methods are typically based on Monte Carlo ray tracing. These include far-field radiative transfer and coherent backscattering methods and their extensions incorporating full-wave interactions. Students are engaged in developing numerical methods for specific scattering problems. The development and computations take place in both laptop and supercomputing environments.

Course is held on Mondays 10-12 and Tuesdays 14-16, but there are exceptions described in the information package below. Lectures are given in the Physicum lecture rooms D116 and D115. Exercise sessions are in Physicum D115, Thursdays 14-16.

Lectures by Karri Muinonen, Anne Virkki, and Antti Penttilä, and exercises by Vesa Björn.

Recommended preliminary knowledge: basic courses in Physics, basic courses in Mathematics, Electrodynamics, Mathematical Methods for Physicists I & II, Scientific Computing I.

Information

Information package

Lecture material

Lecture 1
Lecture 2: notes 2a, notes 2b, notes 2c
Lecture 3, notes 3a, notes 3b, notes 3c, notes 3d
Lecture 4, notes 4a, notes 4b, notes 4c, notes 4d, notes 4e, notes 4f, notes 4g
Lecture 5, notes 5a, notes 5b, notes 5c, notes 5d, notes 5e
Lecture 6, notes 6a, notes 6b, notes 6c
Lecture 7, notes 7a, notes 7b
Lecture 8, notes 8a, notes 8b, notes 8c, notes 8d
Lecture 9, notes 9a, notes 9b, notes 9c
Lecture 10, notes 10a, notes 10b, notes 10c
Lecture 11
Lecture 12, notes 12a, notes 12b, notes12c, notes12d

Exercises

Project tasks

Background material

P. C.Y. Chang, J.G. Walker, K.I. Hopcraft. Ray tracing in absorbing media. JQSRT 96 (2005).
Mie codes in Python: mie.py or in Fortran77:mie.f
Mishchenko's T-matrix code for particles in random orientation, modified to read parameters from an input file: tmd-lp.f, lpd.f, tmd.par.f. An example input file default.in, and article explaining the parameters: 98_jqsrt_60_309.pdf
Mackowski's MSTM code: src-v3.0.1, and example input file: mstm-input.inp
Example input files for RT-CB code: rayleigh-plane.inp
Alternative Makefile for RT-CB, copy to directory src\dsfmt under the rt-cb root folder