Ablative Richtmyer-Meshkov and Rayleigh-Taylor instabilities in direct-drive laser fusion and growth reduction by adiabat shaping

One of the main design objectives for Inertial Confinement Fusion is the specification of surface roughness: surface perturbation triggers ablative instabilities that can cause shell rupture and/or hot-cold fuel mixing preventing the target from igniting. Understanding, controlling and measuring instabilities evolution is fundamental in order to design robust and efficient targets. The present work focuses on the ablative Rayleigh-Taylor instability (a-RTI); the a-RTI dispersion relation for high modes for a CH-DT-target [1] is presented and compared with a-RTI dispersion relation for an all-DT target [2]. The Ablative region and the Blow-off region are characterized via lagrangian line envelope graphs and isodensity line envelope graphs.