A fast solution method for the Radiative Transfer Equation and its applications in propagation of EM waves through sparsely populated discrete media

We present elements of an algorithm suitable to accelerating solution of the three-dimensional Radiative Transfer Equation (RTE) in its integral form, for applications in the context of electromagnetic wave propagation through dilute discrete media, e.g., clouds. Our approach is based on matrix compression and fast matrix-vector utilizing Fast Fourier Transforms (FFTs). We also outline a fast solution scheme for a generalization of the RTE to denser media.