259 / 2023-04-22 21:21:21

First cross beam energy transfer experiment on Shenguang-100 kJ laser facility

Cross beam energy transfer,Shenguang-100 kJ,Wavelength difference

惯性约束聚变物理学 > 黑腔和激光等离子体相互作用-II

The Shenguang-100 kJ laser facility, which is currently the primary platform for indirect-drive inertial confinement fusion research in China, was upgraded in 2022 to operate at different wavelengths among beams. With this capability, the first cross beam energy transfer (CBET) experiment was carried out recently, by injecting 24 laser beams through a laser entrance hole into a shortened gas-filled hohlraum. Two of the inner beams (28.5° and 35° relative to the hohlraum axis, respectively) hit a gold witness plate after transmitting through the hohlraum. The generated x-ray spots, together with several additional spots produced by calibration beams with known intensities on another neighboring plate, were recorded by an x-ray frame camera, which provided a way to infer the powers of the transmitted inner beams. The results displayed a prominent CBET process as the wavelength difference between the inner and outer beams was increased. A maximum enhancement of ~80% in the peak power of inner beams was recorded, corresponding to an enhancement of ~60% in the x-ray flux of the spot, which was measured by a space-resolving flux detector. These results were favorably reproduced by simulations and would play an important role in subsequent integrated experiments, which had suffered a long-standing issue of drive deficit at the hohlraum waist.