Irradiation uniformity of directly driven inertial confinement fusion targets in the context of the shock-ignition scheme

In direct drive inertial confinement fusion (ICF) the uniformity of the irradiation of the capsule still represents a crucial issue. The quality of the capsule irradiation in the context of the shock-ignition (SI) scheme has been assessed numerically. Schemes characterized by different directions of irradiation associated with a single laser beam or a bundle of laser beams have been considered. Beam imperfections as power imbalance and pointing errors have been taken into account and show that the focal spot that minimizes the root-mean-square deviation depends on these beam imperfections. We discuss the advantages provided by laser facilities accounting for a large number (up to a few thousand) of beamlets. Preliminarily results concerning the use of the Laser-Megajoule facility associated with a SI scheme will be discussed.