The paper presents the results of the numerical solution (the Monte-Carlo method) of the nonstationary radiation transfer equation in an optically dense disperse medium. As a model of the medium, the presence of a polydisperse water cloud is assumed. It is expected that an ultrashort (about 50 fs) and ultraintense laser pulse stimulates the nonstationary transition proceses in the scattering particle volume resulting in time transformation of their optical characteristics and, primarily, the scattering phase function. To calculate the time dynamics of the scattering phase function of a laser pulse by a transparent spherical particle the nonstationary Mie theory was used, based on the Fourier representation of the original light pulse and the linear theory of radiation diffraction at a sphere. These estimates were used as the input parameters for numerical solution of the integral transfer equation with a time-dependent kernel. Preliminary results indicate the possibility of a considerable enhancement of the backscattering signal due to the anisotropy reduction of the cloud droplet scattering phase function.
light scattering, femtosecond pulse, Monte Carlo method