A novel three-axis cylindrical hohlraum designed for inertial confinement fusion ignition

Abstract

A novel ignition hohlraum for indirect-drive inertial confinement fusion is proposed, which is named three-axis cylindrical hohlraum (TACH). TACH is a kind of 6 laser entrance holes (LEHs) hohlraum, which is orthogonally jointed of three cylindrical hohlraums. Laser beams are injected through every entrance hole with the same incident angle of 55°. A view-factor simulation result shows that the time-varying drive asymmetry of TACH is less than 1.0% in the whole drive pulse period without any supplementary technology. Coupling efficiency of TACH is close to that of 6 LEHs spherical hohlraum with corresponding size. Its plasma-filling time is close to that of typical cylindrical ignition hohlraum. Its laser plasma interaction has as low backscattering as the outer cone of the cylindrical ignition hohlraum. Therefore, TACH combines most advantages of various hohlraums and has little predictable risk, providing an important competitive candidate for ignition hohlraum.

Target alignment in the Shen-Guang II Upgrade laser facility

“…Six-LEH hohlraums [13][14][15] , as shown in Figure 15, have one more rotational degree of freedom and two more laser entrance directions compared to cylindrical targets. It is very difficult to align such a hohlraum with the TAS, which is designed for use with a cylindrical hohlraum.…”

“…Over the past 3 years, work has shown that a spherical hohlraum with six laser entrance holes (LEHs) [13, 14] or a three-axis cylindrical hohlraum (TACH) [15] , which contains three orthogonally joined cylindrical hohlraums and six LEHs – with high symmetry on a capsule, and low possibility of plasma jet generation – seems superior to a cylindrical target. With more LEHs to be positioned and the shooting laser from six directions to be aligned, this target poses new challenges for alignment.…”

Recent progress of hohlraum physics experiments in indirect-driven ICF in China

“…在最近的研究工作中我们又提出了六通柱腔 [42] (图22(a))、三轴柱腔 [43] [45] 、Au-U-Dy鸡尾酒黑腔 [46] 图 23 (网络版彩图)神光Ⅲ原型装置上的纯Au腔和UN涂 层U腔X光能谱对比 [47] Figure 23 (Color online) The X-ray spectra from Au hohlraum and UN-coated DU hohlraum on SG-Ⅲ prototype [47].…”

Preliminary study on a tetrahedral hohlraum with four half-cylindrical cavities for indirectly driven inertial confinement fusion

“…However, the overlap and cross of laser beams may arouse nonlinear phenomena and complicated laser-plasma interaction issues [35], such as the daunting SRS and CBET. Recently, a spherical hohlraum with 6LEHs [36] and a novel hohlraum with a three-axis cylindrical hohlraum [37,38], all of which utilize a single-cone beam without any supplementary technology of beam phasing, are proposed to improve these issues, especially the propagation of the inner-cone beams. These hohlraum configurations have natural superiority in maintaining high drive symmetry during the entire capsule implosion process [37][38][39].…”