The SG-Ⅲlaser facility(SG-Ⅲ)is the largest laser driver for inertial confinement fusion(ICF)researches in China,which has 48 beamlines and can deliver 180 kJ ultraviolet laser energy in 3 ns.In order to meet the req...The SG-Ⅲlaser facility(SG-Ⅲ)is the largest laser driver for inertial confinement fusion(ICF)researches in China,which has 48 beamlines and can deliver 180 kJ ultraviolet laser energy in 3 ns.In order to meet the requirements of precise physics experiments,some new functionalities need to be added to SG-Ⅲand some intrinsic laser performances need upgrade.So at the end of SG-Ⅲ's engineering construction,the 2-year laser performance upgrade project started.This paper will introduce the newly added functionalities and the latest laser performance of SG-Ⅲ.With these function extensions and performance upgrade,SG-Ⅲis now fully prepared for precise ICF experiments and solidly paves the way towards fusion ignition.展开更多
Gold disk targets were irradiated using focusing and beam smoothing methods on Xingguang (XG-Ⅱ) laser facilities with 350 nm wavelength,0.6 ns pulse width and 20-80 Joules energies. Laser absorption,light scattering ...Gold disk targets were irradiated using focusing and beam smoothing methods on Xingguang (XG-Ⅱ) laser facilities with 350 nm wavelength,0.6 ns pulse width and 20-80 Joules energies. Laser absorption,light scattering and X-ray conversion were experimentally investigated. The experimental results showed that laser ab-sorption and scattered light were about 90% and 10%,respectively,under focusing irradiation,but the laser absorption increased 5%-10% and the scattered light about 1% under the condition of beam smoothing. Compared with the case of fo-cusing irradiation,the laser absorption was effectively improved and the scattered light remarkably dropped under uniform irradiation; then due to the decrease in laser intensity,X-ray conversion increased. This is highly advantageous to the in-ertial confinement fusion. However,X-ray conversion mechanism basically did not change and X-ray conversion efficiency under beam smoothing and focusing irra-diation was basically the same.展开更多
A multistep pulse compressor(MPC)based on a single-pass single-grating pair(SSGP)is proposed to simplify the entire multi-petawatt(PW)compressor.Only one grating pair with relatively long perpendicular distance is use...A multistep pulse compressor(MPC)based on a single-pass single-grating pair(SSGP)is proposed to simplify the entire multi-petawatt(PW)compressor.Only one grating pair with relatively long perpendicular distance is used to generate the same amount of spectral chirp compared with a four-grating main compressor.As SSGP compressor induces the largest spatial chirp,it can introduce the best beam-smoothing effect to the laser beam on the last grating.When considering the diffraction loss of only two gratings,the total compression efficiency of the SSGP compressor is even larger than that of a four-grating main compressor.Furthermore,the wavefront aberration induced by the SSGP compressor can be better compensated by using deformable mirrors;however,it is difficult or complicated to be well compensated in a four-grating compressor.Approximately 50-100 PW laser pulses can be obtained using this SSGP-based multistage-smoothing MPC with a single laser beam.展开更多
基金This work is supported by the SG-Ⅲ performance upgrade project.
文摘The SG-Ⅲlaser facility(SG-Ⅲ)is the largest laser driver for inertial confinement fusion(ICF)researches in China,which has 48 beamlines and can deliver 180 kJ ultraviolet laser energy in 3 ns.In order to meet the requirements of precise physics experiments,some new functionalities need to be added to SG-Ⅲand some intrinsic laser performances need upgrade.So at the end of SG-Ⅲ's engineering construction,the 2-year laser performance upgrade project started.This paper will introduce the newly added functionalities and the latest laser performance of SG-Ⅲ.With these function extensions and performance upgrade,SG-Ⅲis now fully prepared for precise ICF experiments and solidly paves the way towards fusion ignition.
文摘Gold disk targets were irradiated using focusing and beam smoothing methods on Xingguang (XG-Ⅱ) laser facilities with 350 nm wavelength,0.6 ns pulse width and 20-80 Joules energies. Laser absorption,light scattering and X-ray conversion were experimentally investigated. The experimental results showed that laser ab-sorption and scattered light were about 90% and 10%,respectively,under focusing irradiation,but the laser absorption increased 5%-10% and the scattered light about 1% under the condition of beam smoothing. Compared with the case of fo-cusing irradiation,the laser absorption was effectively improved and the scattered light remarkably dropped under uniform irradiation; then due to the decrease in laser intensity,X-ray conversion increased. This is highly advantageous to the in-ertial confinement fusion. However,X-ray conversion mechanism basically did not change and X-ray conversion efficiency under beam smoothing and focusing irra-diation was basically the same.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.61527821,61905257,and U1930115)the Shanghai Municipal Science and Technology Major Project(No.2017SHZDZX02)
文摘A multistep pulse compressor(MPC)based on a single-pass single-grating pair(SSGP)is proposed to simplify the entire multi-petawatt(PW)compressor.Only one grating pair with relatively long perpendicular distance is used to generate the same amount of spectral chirp compared with a four-grating main compressor.As SSGP compressor induces the largest spatial chirp,it can introduce the best beam-smoothing effect to the laser beam on the last grating.When considering the diffraction loss of only two gratings,the total compression efficiency of the SSGP compressor is even larger than that of a four-grating main compressor.Furthermore,the wavefront aberration induced by the SSGP compressor can be better compensated by using deformable mirrors;however,it is difficult or complicated to be well compensated in a four-grating compressor.Approximately 50-100 PW laser pulses can be obtained using this SSGP-based multistage-smoothing MPC with a single laser beam.
