Gasbag targets are useful for the research of laser-plasma interactions in inertial confinement fusion,especially in the laser overlapping regime.We report that on the Shengguang-II laser facility,millimeter−scale pla...Gasbag targets are useful for the research of laser-plasma interactions in inertial confinement fusion,especially in the laser overlapping regime.We report that on the Shengguang-II laser facility,millimeter−scale plasmas are successfully generated by four 0.35µm laser beams using a gasbag target.Multiple diagnostics are applied to characterize the millimeter−scale plasmas in detail.The images from the x-ray pinhole cameras confirm that millimeter-scale plasmas are indeed created.An optical Thomson scattering system diagnoses the electron temperature of the CH filling plasmas by probing the thermal ion-acoustic fluctuations,which indicates that the electron temperature has a 600 eV flat roof in 0.7–1.3 ns.Another key parameter,i.e.the electron density of the millimeter-scale plasmas,is inferred by the spectrum of the back stimulated Raman scattering of an additional 0.53µm laser beam.The inferred electron density keeps stable at 0.1nc in early time consistent with the controlled filling pressure and splits into a higher density in late time,which is attributed to the blast wave entering into the SRS interaction region.展开更多
A shock-timing experiment plays an important role in inertial confinement fusion studies,and the timing of multiple shock waves is crucial to the performance of inertial confinement fusion ignition targets.We present ...A shock-timing experiment plays an important role in inertial confinement fusion studies,and the timing of multiple shock waves is crucial to the performance of inertial confinement fusion ignition targets.We present an experimental observation of a shock wave driven by a two-step radiation pulse in a polystyrene target.The experiment is carried out at Shen Guang III Yuan Xing(SGIIIYX)laser facility in China,and the generation and coalescence of the two shock waves,originating from each of the two radiation steps,is clearly seen with two velocity interferometers.This two-shock-wave coalescence is also simulated by the radioactive hydrodynamic code of a multi-1D program.The experimental measurements are compared with the simulations and quite good agreements are found,with relatively small discrepancies in shock timing.展开更多
In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the...In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S^1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 11005097the Project 9140C6801010901 of China Academy of Engineering Physics+1 种基金the National Natural Science Foundation of China under Grant No 11175179the Knowledge Innovation Project of Chinese Academy of Sciences under Grant No KJCX2-YW-N36.
文摘Gasbag targets are useful for the research of laser-plasma interactions in inertial confinement fusion,especially in the laser overlapping regime.We report that on the Shengguang-II laser facility,millimeter−scale plasmas are successfully generated by four 0.35µm laser beams using a gasbag target.Multiple diagnostics are applied to characterize the millimeter−scale plasmas in detail.The images from the x-ray pinhole cameras confirm that millimeter-scale plasmas are indeed created.An optical Thomson scattering system diagnoses the electron temperature of the CH filling plasmas by probing the thermal ion-acoustic fluctuations,which indicates that the electron temperature has a 600 eV flat roof in 0.7–1.3 ns.Another key parameter,i.e.the electron density of the millimeter-scale plasmas,is inferred by the spectrum of the back stimulated Raman scattering of an additional 0.53µm laser beam.The inferred electron density keeps stable at 0.1nc in early time consistent with the controlled filling pressure and splits into a higher density in late time,which is attributed to the blast wave entering into the SRS interaction region.
基金by the National Natural Science Foundation of China under Grant No 10805041Science and Technology on Plasma Physics Laboratory under Grant No 9140C6801021001.
文摘A shock-timing experiment plays an important role in inertial confinement fusion studies,and the timing of multiple shock waves is crucial to the performance of inertial confinement fusion ignition targets.We present an experimental observation of a shock wave driven by a two-step radiation pulse in a polystyrene target.The experiment is carried out at Shen Guang III Yuan Xing(SGIIIYX)laser facility in China,and the generation and coalescence of the two shock waves,originating from each of the two radiation steps,is clearly seen with two velocity interferometers.This two-shock-wave coalescence is also simulated by the radioactive hydrodynamic code of a multi-1D program.The experimental measurements are compared with the simulations and quite good agreements are found,with relatively small discrepancies in shock timing.
基金the National Natural Science Foundation of China(Grant No. 10576041)
文摘In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S^1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.
