Huigang Wei
Chinese Academy of Sciences
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Publication
Featured researches published by Huigang Wei.
Physical Review Letters | 2012
Q. L. Dong; S. Wang; Quanming Lu; Can Huang; Dawei Yuan; Xufeng Liu; X. X. Lin; Yu-Tong Li; Huigang Wei; Jiayong Zhong; Shi; Shuqing Jiang; Yongkun Ding; Jiang Bb; Kai Du; X. T. He; M. Y. Yu; Cheng Liu; S. J. Wang; Yong-Jian Tang; Jianqiang Zhu; G. Zhao; Z. M. Sheng; Jie Zhang
Reconnection of the self-generated magnetic fields in laser-plasma interaction was first investigated experimentally by Nilson et al. [Phys. Rev. Lett. 97, 255001 (2006)] by shining two laser pulses a distance apart on a solid target layer. An elongated current sheet (CS) was observed in the plasma between the two laser spots. In order to more closely model magnetotail reconnection, here two side-by-side thin target layers, instead of a single one, are used. It is found that at one end of the elongated CS a fanlike electron outflow region including three well-collimated electron jets appears. The (>1 MeV) tail of the jet energy distribution exhibits a power-law scaling. The enhanced electron acceleration is attributed to the intense inductive electric field in the narrow electron dominated reconnection region, as well as additional acceleration as they are trapped inside the rapidly moving plasmoid formed in and ejected from the CS. The ejection also induces a secondary CS.
The Astrophysical Journal | 2008
Huigang Wei; J. R. Shi; Gang Zhao; Yi Zhang; Quan-Li Dong; Yu-Tong Li; Shoujun Wang; Jie Zhang; Zuotang Liang; Jiyan Zhang; T. S. Wen; Wenhai Zhang; Xin Hu; Shenye Liu; Yongkun Ding; Lin Zhang; Yong-Jian Tang; Baohan Zhang; Zhijian Zheng; Hiroaki Nishimura; Shinsuke Fujioka; Feilu Wang; Hideaki Takabe
Measurements of the opacity of silicon at high temperature and high density are reported. A silicon dioxide foam was heated by eight nanosecond laser beams while a backlighter X-ray source was produced with a picosecond laser. Absorptions of the 1-2 transitions of Si XII through Si VI were observed in the wavelength range from 6.6 to 7.1 A. The experimental results are simulated with theoretical calculations under local thermodynamic equilibrium using a detailed level accounting model and can be reproduced in general when the effects of the oxygen in the SiO2 are taken into account.
Physics of Plasmas | 2009
E. Brambrink; Huigang Wei; Benjamin Barbrel; P. Audebert; A. Benuzzi-Mounaix; T. R. Boehly; Takuma Endo; C. D. Gregory; Tsuyoshi Kimura; R. Kodama; N. Ozaki; H.-S. Park; M. Rabec Le Gloahec; M. Koenig
Studies of short-pulse laser-generated hard x-ray (18–60 keV) sources, suitable for radiographs of large samples of dense matter, are presented. The spatial and dynamic resolutions for different target types and laser parameters have been investigated. A high quality radiograph with good spatial resolution in two dimensions was demonstrated by irradiating freestanding thin W wires. The influence of the geometry for the quality of the radiograph, which is crucial for the design of experiments probing laser-compressed matter, is reported.
Physics of Plasmas | 2016
Xiaoxing Pei; J. Y. Zhong; Youichi Sakawa; Zhaochuan Zhang; Kai Zhang; Huigang Wei; Yi Li; Y. F. Li; Beibei Zhu; Takayoshi Sano; Y. Hara; S. Kondo; Shinsuke Fujioka; G. Y. Liang; Fengchao Wang; G. Zhao
We demonstrate a novel plasma device for magnetic reconnection, driven by Gekko XII lasers irradiating a double-turn Helmholtz capacitor-coil target. Optical probing revealed an accumulated plasma plume near the magnetic reconnection outflow. The background electron density and magnetic field were measured to be approximately 1018 cm−3 and 60 T by using Nomarski interferometry and the Faraday effect, respectively. In contrast with experiments on magnetic reconnection constructed by the Biermann battery effect, which produced high beta values, our beta value was much lower than one, which greatly extends the parameter regime of laser-driven magnetic reconnection and reveals its potential in astrophysical plasma applications.
Applied Physics Letters | 2015
Beibei Zhu; Yi Li; Dawei Yuan; Yifei Li; Fang Li; Guoqian Liao; J. R. Zhao; Jia-Yong Zhong; F. B. Xue; Shukai He; Weiwu Wang; Feng Lu; Faqiang Zhang; Lei Yang; Kainan Zhou; Na Xie; Wei Hong; Huigang Wei; Kai Zhang; Bo Han; Xiaoxing Pei; Chang Liu; Z. D. Zhang; W. M. Wang; Jianqiang Zhu; Y. Q. Gu; Zongqing Zhao; B. H. Zhang; G. Zhao; Jie Zhang
A simple scheme to produce strong magnetic fields due to cold electron flow in an open-ended coil heated by high power laser pulses is proposed. It differs from previous generation of magnetic fields driven by fast electron current in a capacitor-coil target [S. Fujioka et al., Sci. Rep. 3, 1170 (2013)]. The fields in our experiments are measured by B-dot detectors and proton radiography, respectively. A 205 T strong magnetic field at the center of the coil target is generated in the free space at Iλ2 of 6.85 × 1014 W cm−2 μm2, where I is the laser intensity, and λ is the laser wavelength. The magnetic field strength is proportional to Iλ2. Compared with the capacitor-coil target, the generation mechanism of the magnetic field is straightforward and the coil is easy to be fabricated.
Astrophysical Journal Supplement Series | 2016
J. Y. Zhong; J. Lin; Yi Li; X. G. Wang; Y. T. Li; Kai Zhang; Dawei Yuan; Y. L. Ping; Huigang Wei; J.Q. Wang; LuNing Su; F. Li; Bo Han; Guoqian Liao; Chuanlei Yin; Yuan Fang; Xiaohui Yuan; C. Wang; J. R. Sun; G. Y. Liang; Feilu Wang; Y. K. Ding; X. T. He; Jianqiang Zhu; Zheng-Ming Sheng; Gang Li; Gang Zhao; Zhang J
Laboratory experiments have been carried out to model the magnetic reconnection process in a solar flare with powerful lasers. Relativistic electrons with energy up to megaelectronvolts are detected along the magnetic separatrices bounding the reconnection outflow, which exhibit a kappa-like distribution with an effective temperature of ~109 K. The acceleration of non-thermal electrons is found to be more efficient in the case with a guide magnetic field (a component of a magnetic field along the reconnection-induced electric field) than in the case without a guide field. Hardening of the spectrum at energies ≥500 keV is observed in both cases, which remarkably resembles the hardening of hard X-ray and γ-ray spectra observed in many solar flares. This supports a recent proposal that the hardening in the hard X-ray and γ-ray emissions of solar flares is due to a hardening of the source-electron spectrum. We also performed numerical simulations that help examine behaviors of electrons in the reconnection process with the electromagnetic field configurations occurring in the experiments. The trajectories of non-thermal electrons observed in the experiments were well duplicated in the simulations. Our numerical simulations generally reproduce the electron energy spectrum as well, except for the hardening of the electron spectrum. This suggests that other mechanisms such as shock or turbulence may play an important role in the production of the observed energetic electrons.
Astronomy and Astrophysics | 2010
Huigang Wei; J. R. Shi; Gang Zhao; Z. T. Liang
Context. Atomic data for K-shell transitions are essential for modeling the K absorption lines, which have been observed in the spectra of active galaxies by high-resolution X-ray observatories, e.g. XMM, Chandra, and Suzaku. These accurate atomic data are also needed for line identifications and spectroscopic diagnostic of plasmas in laboratory generated by laser or beam-foil method. Aims. We calculate atomic data using the atomic code flexible atomic code (FAC) taking relativistic effects and configuration interactions into account.
Scientific Reports | 2017
Dawei Yuan; Yu-Tong Li; Meng Liu; Jiayong Zhong; Baojun Zhu; Yanfei Li; Huigang Wei; Bo Han; Xiaoxing Pei; Jiarui Zhao; Fang Li; Zhe Zhang; G. Y. Liang; Feilu Wang; Su-Ming Weng; Yingjun Li; Shaoen Jiang; Kai Du; Yongkun Ding; Baoqiang Zhu; Jianqiang Zhu; Gang Zhao; Jie Zhang
A pair of collisionless shocks that propagate in the opposite directions are firstly observed in the interactions of laser-produced counter-streaming flows. The flows are generated by irradiating a pair of opposing copper foils with eight laser beams at the Shenguang-II (SG-II) laser facility. The experimental results indicate that the excited shocks are collisionless and electrostatic, in good agreement with the theoretical model of electrostatic shock. The particle-in-cell (PIC) simulations verify that a strong electrostatic field growing from the interaction region contributes to the shocks formation. The evolution is driven by the thermal pressure gradient between the upstream and the downstream. Theoretical analysis indicates that the strength of the shocks is enhanced with the decreasing density ratio during both flows interpenetration. The positive feedback can offset the shock decay process. This is probable the main reason why the electrostatic shocks can keep stable for a longer time in our experiment.
Physics of Plasmas | 2010
Quan-Li Dong; Shoujun Wang; Yu-Tong Li; Yi Zhang; Jing Zhao; Huigang Wei; J. R. Shi; Gang Zhao; Jiyan Zhang; Y. Q. Gu; Yongkun Ding; T. S. Wen; Wenhai Zhang; Xin Hu; Shenye Liu; Lin Zhang; Yong-Jian Tang; Baohan Zhang; Zhijian Zheng; Hiroaki Nishimura; Shinsuke Fujioka; Feilu Wang; Hideaki Takabe; Jie Zhang
The temporally and spatially resolved characteristics of silicon dioxide aerogel plasmas were studied using x-ray spectroscopy. The plasma was generated in the near-Planckian radiation environment within gold hohlraum targets irradiated by laser pulses with a total energy of 2.4 kJ in 1 ns. The contributions of silicon ions at different charge states to the specific components of the measured absorption spectra were also investigated. It was found that each main feature in the absorption spectra of the measured silicon dioxide aerogel plasmas was contributed by two neighboring silicon ionic species.
Bulletin of the American Physical Society | 2009
Huigang Wei; E. Brambrink; A. Benuzzi-Mounaix; A. Ravasio; G. Morard; T. de Rességuier; Emilien Lescoute; Norimasa Ozaki; Kohei Miyanishi; Gang Zhao; Z. T. Liang; M. Koenig; F. Guyot
We use directly driven method to compress the iron along isentropic path. By adjusting the pulse intensity of laser to increase with time, we directly ablated the iron target with laser to achieve isentropic compression. Rear surface velocities of the iron targets were recorded by VISAR (Velocity Interferometer System for Any Reflector). The iron (bcc) to (hcp) phase transformation was clearly observed. Experiment results were compared with simulations