title: Formation and evolution of a pair of collisionless shocks in counter-streaming flows.
abstract: 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.
authors.affiliation: Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China.
authors.forename: Dawei
authors.initials: D
authors.lastname: Yuan
authors.affiliation: National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.|Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China.|School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yutong
authors.initials: Y
authors.lastname: Li
authors.affiliation: Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China.|Key Laboratory for Laser Plasmas (MoE), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Liu
authors.affiliation: Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China.|Department of Astronomy, Beijing Normal University, Beijing 100875, China.
authors.forename: Jiayong
authors.initials: J
authors.lastname: Zhong
authors.affiliation: National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Baojun
authors.initials: B
authors.lastname: Zhu
authors.affiliation: National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Yanfei
authors.initials: Y
authors.lastname: Li
authors.affiliation: Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China.
authors.forename: Huigang
authors.initials: H
authors.lastname: Wei
authors.affiliation: Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Han
authors.affiliation: Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China.
authors.forename: Xiaoxing
authors.initials: X
authors.lastname: Pei
authors.affiliation: National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Jiarui
authors.initials: J
authors.lastname: Zhao
authors.affiliation: National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Li
authors.affiliation: National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China.
authors.forename: Guiyun
authors.initials: G
authors.lastname: Liang
authors.affiliation: Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China.
authors.forename: Feilu
authors.initials: F
authors.lastname: Wang
authors.affiliation: Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China.|Key Laboratory for Laser Plasmas (MoE), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Suming
authors.initials: S
authors.lastname: Weng
authors.affiliation: State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Beijing 100083, China.
authors.forename: Yingjun
authors.initials: Y
authors.lastname: Li
authors.affiliation: Research Center for Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China.
authors.forename: Shaoen
authors.initials: S
authors.lastname: Jiang
authors.affiliation: Research Center for Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Du
authors.affiliation: Research Center for Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China.
authors.forename: Yongkun
authors.initials: Y
authors.lastname: Ding
authors.affiliation: National Laboratory on High Power Laser and Physics, Chinese Academy of Sciences, Shanghai 201800, China.
authors.forename: Baoqiang
authors.initials: B
authors.lastname: Zhu
authors.affiliation: National Laboratory on High Power Laser and Physics, Chinese Academy of Sciences, Shanghai 201800, China.
authors.forename: Jianqiang
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Zhao
authors.affiliation: Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China.|Key Laboratory for Laser Plasmas (MoE), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang