Multiple Scattering Theory in One Dimensional Space and Time Dependent Disorder: Average Field

We theoretically study the propagation of light in one-dimensional space- and timedependent disorder. The disorder is described by a fluctuating permittivity epsilon(x, t) exhibiting short-range correlations in space and time, without cross correlation between them. Depending on the illumination conditions, we show that the intensity of the average field decays exponentially in space or in time, with characteristic length or time defining the scattering mean -free path is and the scattering mean -free time Ts. In the weak scattering regime, we provide explicit expressions for is and Ts , that are checked against rigorous numerical simulations.