Speaker
Description
See the full abstract here http://ocs.ciemat.es/EPS2019ABS/pdf/O3.204.pdf
For the last couple of years, large efforts have been invested at CEA/DAM to develop the 3D radiationhydrodynamics code TROLL. Indeed, 2D radhydro codes are the main tool to design and analyze HED and ICF experiments. Yet, many of the first are intrinsically 3D, for example: few laser beams in directdrive or study objects on the equatorial plane of a hohlraum in indirect drive. For the second, the axisymmetry is assumed due to the number of beams per irradiation ring. Yet, numerous studies pinpointed the importance of 3D effects, in particular for the expansion of the outer plasma bubbles, which affects the propagation of the inner cone beams. Finally, in the framework of the progressive commissioning of LMJ up to its final 44 quads configuration, ICF experiments might be conducted with suboptimal azimuthal laser irradiation. While the TROLL code has already been challenged by numerous 3D hohlraum experiments, questions remained about its capability to simulate indirect drive implosions with a poor azimuthal irradiation symmetry. In order to tackle this, an experiment has been performed in 2018 at the Omega laser facility (LLE, U. of Rochester), during which a rugby hohlraum was driven either by 18 beams at full power (asymmetric irradiation) or 30 beams at 3/5 power (symmetric irradiation), such as to keep the cavity energetics constant. Three types of targets were used to asses the effects of the asymmetry : reemits for early time, foamballs for intermediate time and D2 filled capsules for late / integrated time measurements. We will present the design, results, and interpretation of this experiment, validating now TROLL for 3D implosion calculations, and paving the way for the design of more ambitious ICF experiments on the LMJ.
