Polar direct drive illumination uniformity provided by the Orion facility

Abstract

The ten long-pulse laser beams of the Orion facility have been considered as a direct driver for the irradiation of a spherical capsule. The intrinsic root-mean-square illumination non-uniformity σ0 has been evaluated assuming circular and elliptical super-Gaussian laser intensity profiles. Calculations accounting for nominal uncertainties in power imbalance, pointing error and target positioning have shown a degradation of the irradiation uniformity. Non-uniformity of the irradiation as a function of the capsule radius has been calculated and it has been shown that the use of the polar direct drive technique significantly improves the quality of the irradiation. Finally, it is found that an elliptical focal shape provides better symmetry results in comparison to circular ones, whilst the laser-capsule coupling is reduced. © EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2013.