To achieve ignition with high gain in inertial confinement fusion, precise symmetry control is one of the key issues to guarantee the PdV work converting into the inner energy efficiently and maximize the pressure of the hot spot. The shaped pulse is used to maintain a low adiabat of the shell. A longer pulse and more compressible shell require more rigorous symmetry control, especially the driven symmetry during the picket pulse and main pulse. A surrogate capsule with high Z materials is usually used for the early-time symmetry tuning. The passive diagnosis of the re-emission spheres gives the time-resolved measurement of the first 2 ns, and the precision is mainly affected by the weak signals due to the low radiation temperature of the hohlraum. To compare with the re-emission technique with high Z surrogate capsule, we demonstrated the early-time symmetry tuning for picket pulse by using thin-shell capsule radiography technique. Combined with 1D hydrodynamics simulation and backlit imaging simulation, the driven asymmetry was quantified. A view factor assessment was also carried out by IRAD3D and coincided with the experimental consequences.

中文翻译：

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薄壳胶囊放射成像对脉冲内爆的早期对称性量化

为了在惯性约束聚变中以高增益实现点火，精确的对称控制是确保PdV功有效地转换为内能并使热点压力最大化的关键问题之一。整形后的脉冲用于维持外壳的低绝热。更长的脉冲和更易压缩的外壳需要更严格的对称性控制，尤其是在纠察脉冲和主脉冲期间的驱动对称性。高Z材料的替代胶囊通常用于早期对称性调整。重新发射球体的被动诊断给出了前2 ns的时间分辨测量结果，而精确度主要受因小球辐射温度低而产生的微弱信号的影响。为了与高Z替代胶囊的再发射技术进行比较，我们通过使用薄壳胶囊射线照相技术演示了纠察脉冲的早期对称调整。结合一维流体动力学模拟和背光成像模拟，对驱动的不对称性进行了量化。IRAD3D还进行了视点评估，并与实验结果相吻合。