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Your search keyword '"Yang, Xiao-Hu"' showing total 11 results
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11 results on '"Yang, Xiao-Hu"'

5. Enhancement of positron yields using multi-layer targets irradiated by laser-induced energetic electrons

Author

Peng, Meng, Ma, Yan-Yun, Li, Bo-Yuan, Tian, Li-Chao, Jiang, Jing, Zi, Ming, and Yang, Xiao-Hu

Subjects
Materials Science (miscellaneous), Biophysics, General Physics and Astronomy, Physical and Theoretical Chemistry, Mathematical Physics
Abstract

Positrons with high energy and short pulse duration generated by the ultra-short and ultra-intense laser interaction with a two-target system (under-density plasma target and high-Z metal target) have wide applications. In this paper, we proposed an optimal scheme for enhancing positrons with multi-layer high-Z converters. Positrons with larger divergence escape from the target zone, reducing positron annihilation in the target, while secondary particles with smaller divergence react with the subsequent target to produce more positrons. The total positron yield and positron beam divergence increased obviously with the target number when using the thin converter, while the scenario was reversed for the recorded positrons. The total positrons produced by bilayer 5-mm targets and eight-layer 1-mm targets increased by 14% and 62%, respectively, compared to the outgoing positrons produced by an 8-mm monolayer target. Positron yields can be further enhanced by adjusting the thickness of the subsequent target and distance, according to the intensity and angular distribution of positrons emitted from the previous target.

Published
2022
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10. Radiation effects of electrons on multilayer FePS3 studied with laser plasma accelerator.

Author

Peng, Meng, Yang, Jun-Bo, Chen, Hao, Li, Bo-Yuan, Ge, Xu-Lei, Yang, Xiao-Hu, Zhang, Guo-Bo, and Ma, Yan-Yun

Subjects
LASER plasma accelerators, ELECTRON beams, PARTICLE beams, RADIATION, RADIATION sources, ELECTRONS, SURFACE structure
Abstract

Space radiation with inherently broadband spectral flux poses a huge danger to astronauts and electronics on aircraft, but it is hard to simulate such feature with conventional radiation sources. Using a tabletop laser-plasma accelerator, we can reproduce exponential energy particle beams as similar as possible to these in space radiation. We used such an electron beam to study the electron radiation effects on the surface structure and performance of two-dimensional material (FePS3). Energetic electron beam led to bulk sample cleavage and damage between areas of uneven thickness. For the FePS3 sheet sample, electron radiation transformed it from crystalline state to amorphous state, causing the sample surface to rough. The full widths at the half maximum of characteristic Raman peaks became larger, and the intensities of characteristic Raman peaks became weak or even disappeared dramatically under electron radiation. This trend became more obvious for thinner samples, and this phenomenon was attributed to the cleavage of Pâ€"P and Pâ€"S bonds, destabilizing the bipyramid structure of [P2S6]4â€" unit. The results are of great significance for testing the maximum allowable radiation dose for the two-dimensional material, implying that FePS3 cannot withstand such energetic electron radiation without an essential shield. [ABSTRACT FROM AUTHOR]

Published
2022
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11. The importance of Righi–Leduc heat flux to the ablative Rayleigh–Taylor instability during a laser irradiating targets

Author

Cui, Ye, Yang, Xiao-Hu, Ma, Yan-Yun, Zhang, Guo-Bo, Xu, Bi-Hao, Chen, Ze-Hao, Li, Ze, Shao, Fu-Qiu, and Zhang, Jie

Abstract

AbstractThe Righi–Leduc heat flux generated by the self-generated magnetic field in the ablative Rayleigh–Taylor instability driven by a laser irradiating thin targets is studied through two-dimensional extended-magnetohydrodynamic simulations. The perturbation structure gets into a low magnetization state though the peak strength of the self-generated magnetic field could reach hundreds of teslas. The Righi–Leduc effect plays an essential impact both in the linear and nonlinear stages, and it deflects the total heat flux towards the spike base. Compared to the case without the self-generated magnetic field included, less heat flux is concentrated at the spike tip, finally mitigating the ablative stabilization and leading to an increase in the velocity of the spike tip. It is shown that the linear growth rate is increased by about 10% and the amplitude during the nonlinear stage is increased by even more than 10% due to the feedback of the magnetic field, respectively. Our results reveal the importance of Righi–Leduc heat flux to the growth of the instability and promote deep understanding of the instability evolution together with the self-generated magnetic field, especially during the acceleration stage in inertial confinement fusion.

Published
2024
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