Modelling studies of transmission and scattering of high energy laser radiation under remote continental conditions

Kurzfassung

A numerical model is developed to simulate the angle dependent light scattering. The model is based on Mie theory and uses the complex refractive indices of aerosol particles and rain droplets together with their corresponding experimental number size distributions as input parameters. The laser beam parameters of the high energy laser at the DLR laser transmission test range in Lampoldshausen and the geometry of the detection system are taken into consideration. It is demonstrated that the numerical model accurately predicts the absolute scattered powers obtained by a calibrated multiangle light scattering probe measuring under five different scattering angles. The model is applicable for dry and rainy weather conditions. In addition, Mie calculations are performed to determine the extinction coefficients at 1030 nm. The calculated extinction coefficients are correlated with meteorological parameters (i.e. rainfall intensity and visibility) obtained from different types of instruments. The calculated extinction coefficients are compared with the extinction coefficients derived from laser transmission experiments at 1030 nm. A good agreement between numerical results and measurements is observed under rainy weather conditions.