Topics in Particle and Dispersion Science

In the spherical harmonics approach to solving the radiative transfer equation (RTE), the phase function or the phase matrix (for the vector, i.e. polarized light case) and also the radiance (or the Stokes vector) are expanded with respect the spherical harmonic functions (for example, http://en.wikipedia.org/wiki/Spherical_harmonics) and the integrals are calculated analytically. The remaining system of differential equations is solved numerically. Clearly, the spherical harmonics method is identical to the discrete ordinates method for the 0-th order azimuthal harmonic. [AAK]

See also RTE solution, methods, numerical, spherical harmonics and RTE solution for additional references.