LAUSR

We have designed an octahedral spherical hohlraum with 6 laser entrance holes (LEHs) for the Rev. 6 Be ignition capsule [Simakov et al., Phys. Plasmas 21, 022701 (2014)]. With a Au spherical hohlraum of 4400 μm in radius and six LEHs of 1200 μm in radius, a laser pulse of 2.15 MJ energy and 630 TW peak power is required to deliver the radiation drive designed for the Rev. 6 Be ignition capsule. Both our 1D and 2D simulations have shown that the expansion of the Be capsule is very close to or even slightly slower than that of the CH capsule under the same radiation drive inside the spherical hohlraum, in spite of the higher ablation rate of Be. The reason why the Be and CH capsules have similar expansions is due to their similar exhaust velocities, and the reason why CH has a slightly faster expansion is that the CH capsule has a higher opacity which causes the hotter ablated plasmas and then a faster expansion of the CH ablated plasmas. The large volume of the octahedral spherical hohlraum, together with the incident angle of 55° in its laser arrangement, leaves enough room for the laser transportation, thus avoiding the laser being absorbed by Be ablated plasmas and, consequently, avoiding the high risk of laser plasma instabilities. It means that the higher mass ablation rate of Be does not affect the hohlraum energetics and the naturally high symmetry of radiation inside an octahedral spherical hohlraum. Thus, the superior ablation properties of the Be capsule can be fully exploited and hence have a higher opportunity to achieve ignition inside the octahedral spherical hohlraum.We have designed an octahedral spherical hohlraum with 6 laser entrance holes (LEHs) for the Rev. 6 Be ignition capsule [Simakov et al., Phys. Plasmas 21, 022701 (2014)]. With a Au spherical hohlraum of 4400 μm in radius and six LEHs of 1200 μm in radius, a laser pulse of 2.15 MJ energy and 630 TW peak power is required to deliver the radiation drive designed for the Rev. 6 Be ignition capsule. Both our 1D and 2D simulations have shown that the expansion of the Be capsule is very close to or even slightly slower than that of the CH capsule under the same radiation drive inside the spherical hohlraum, in spite of the higher ablation rate of Be. The reason why the Be and CH capsules have similar expansions is due to their similar exhaust velocities, and the reason why CH has a slightly faster expansion is that the CH capsule has a higher opacity which causes the hotter ablated plasmas and then a faster expansion of the CH ablated plasmas. The large volume of the octahedral spherical hohlraum, together with ...