Impact of Cn2 profile structure on Wide Field AO performance

WFAO systems are in their design phase for the ELTs. MCAO (MAORY), LTAO (ATLAS) and MOAO (EAGLE) approaches have been analyzed for the E-ELT. All these approaches require a precise tomographic reconstruction of the turbulent volume. In that frame, Cn2 profiles come up at two levels: the input "true" profile, and the prior profile used as a regularization in the tomographic reconstruction. The impacts of the structure and the complexity of the Cn(2) profile on the residual error after tomographic reconstruction are analyzed and discussed. We show that isoplanatic angle is not sufficient to characterize profiles in WFAO. We highlight the importance of a well sampled Cn(2) input profile and prior profile to be considered in the tomographic reconstructor.