Wavelength-detuning cross-beam energy transfer mitigation scheme for direct drive: Modeling and evidence from National Ignition Facility implosions
Wavelength-detuning cross-beam energy transfer mitigation scheme for direct drive: Modeling and evidence from National Ignition Facility implosions
复制标题
用于直接驱动的波长失谐横梁能量转移缓解方案：来自国家点火设施内爆的建模和证据
DOI：
10.1063/1.5022181
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发表时间：
2017
影响因子：
2.2
通讯作者：
S. Yang
中科院分区：
文献类型：
--
作者：
J. Marozas;M. Hohenberger;M. Rosenberg;D. Turnbull;T. Collins;P. Radha;P. McKenty;J. Zuegel;F. Marshall;S. Regan;T. Sangster;W. Seka;E. Campbell;V. Goncharov;M. Bowers;J. D. Nicola;G. Erbert;B. MacGowan;L. Pelz;J. Moody;S. Yang
跨光束能量传递（CBET）是由种子受激布里渊散射产生的两束能量交换产生的，这不利于直接驱动惯性约束聚变对激光能量的吸收。因此，消融压力和内爆速度受到吸收减少的影响，降低了对称和极性直接驱动下的目标性能。此外，CBET改变了时间分辨散射光谱，重新分配了吸收和散射光变化的壳形态和低模驱动对称性。通过对相互作用光束的激光源波长（±2.3 A UV）进行失谐，在国家点火设施的惯性约束内爆中证明了减轻CBET。在极性直接驱动中，波长失谐可以使赤道区速度提高16%，并改变飞行中的壳形态。这些实验观察结果与辐射-流体动力学模拟的设计预测一致，表明平均烧蚀压力增加了10%。这些结果表明，波长失谐成功地减轻了CBET。仿真预测，利用OMEGA激光系统的三足光束布局，优化的相位板和波长失谐CBET缓解显著增加了吸收，并在对称直接驱动中实现了100-Gbar的热点压力。跨光束能量传递（CBET）是由种子受激布里渊散射产生的两束能量交换产生的，这不利于直接驱动惯性约束聚变对激光能量的吸收。因此，消融压力和内爆速度受到吸收减少的影响，降低了对称和极性直接驱动下的目标性能。此外，CBET改变了时间分辨散射光谱，重新分配了吸收和散射光变化的壳形态和低模驱动对称性。通过对相互作用光束的激光源波长（±2.3 A UV）进行失谐，在国家点火设施的惯性约束内爆中证明了减轻CBET。在极性直接驱动中，波长失谐可以使赤道区速度提高16%，并改变飞行中的壳形态。这些实验观测结果与辐射-流体动力学模拟的设计预测相一致，该预测表明10%的水…
Cross-beam energy transfer (CBET) results from two-beam energy exchange via seeded stimulated Brillouin scattering, which detrimentally reduces laser-energy absorption for direct-drive inertial confinement fusion. Consequently, ablation pressure and implosion velocity suffer from the decreased absorption, reducing target performance in both symmetric and polar direct drive. Additionally, CBET alters the time-resolved scattered-light spectra and redistributes absorbed and scattered-light–changing shell morphology and low-mode drive symmetry. Mitigating CBET is demonstrated in inertial confinement implosions at the National Ignition Facility by detuning the laser-source wavelengths (±2.3 A UV) of the interacting beams. In polar direct drive, wavelength detuning was shown to increase the equatorial region velocity experimentally by 16% and to alter the in-flight shell morphology. These experimental observations are consistent with design predictions of radiation–hydrodynamic simulations that indicate a 10% increase in the average ablation pressure. These results indicate that wavelength detuning successfully mitigates CBET. Simulations predict that optimized phase plates and wavelength-detuning CBET mitigation utilizing the three-legged beam layout of the OMEGA Laser System significantly increase absorption and achieve >100-Gbar hot-spot pressures in symmetric direct drive.Cross-beam energy transfer (CBET) results from two-beam energy exchange via seeded stimulated Brillouin scattering, which detrimentally reduces laser-energy absorption for direct-drive inertial confinement fusion. Consequently, ablation pressure and implosion velocity suffer from the decreased absorption, reducing target performance in both symmetric and polar direct drive. Additionally, CBET alters the time-resolved scattered-light spectra and redistributes absorbed and scattered-light–changing shell morphology and low-mode drive symmetry. Mitigating CBET is demonstrated in inertial confinement implosions at the National Ignition Facility by detuning the laser-source wavelengths (±2.3 A UV) of the interacting beams. In polar direct drive, wavelength detuning was shown to increase the equatorial region velocity experimentally by 16% and to alter the in-flight shell morphology. These experimental observations are consistent with design predictions of radiation–hydrodynamic simulations that indicate a 10% i...