Submitted by Damien GRATADOUR
D. Gratadour (1), E. Gendron (1), F. Rigaut (2), G. Rousset (1)
(1) LESIA - Observatoire de Paris; (2) Gemini observatory
Rayleigh backscattering of laser photons on air molecules is responsible for what is generally called fratricide effect in multiple-LGS AO systems. Using the LIDAR equation, it is possible to compute maps of Rayleigh backscattering for each direction in the pupil. We present the results of such computation for various laser launch configurations on an E-ELT, in the framework of the future ATLAS and EAGLE facilities.