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8月26日学术报告:Stable Electron Beam Generation in LWFAand the Corresponding Research in Laboratory Astrophysics

来源: 发布时间:2024-08-14【字体:

报告人Yanjun Gu

会议时间2024826日(周一)下午13:30

会议地点:强光19号楼四楼会议室

报告内容

Stable electron beam source is critical to the development of Table-top XUV-FEL. In order to maintain the stability and reproducibility of the accelerated electron beam, it requires a stable gas target in the vacuum chamber with precise density distribution profile. It guarantees that the laser-plasma interacts in an optimal density regionand the relative laser focal position doesn't shift too much from shot to shot.In this study, we focus on the instability originated from the gas jet due to the nonlinear fluid dynamics in the supersonic nozzle.By optimizing the driving laser system and gas target, the reproducibility of the acceleration process has been significantly improved.The electron beam with central energy of 380 MeV can be steadily achieved with an energy spread less than 1% and a pointing instability less than 0.5 mrad in RMS.The preliminary proof-of-concept experiment has successfully shown the amplification of the undulator radiation and the possibility of LWFA based FEL.

High energy electron beams driven by LWFA can also be employed in laboratory astrophysics topics such as magnetic reconnection. Fast magnetic field annihilation is accompanied by an electromagnetic burst.Charged particle acceleration is observed in the region of the current sheet formed in the vicinity of the magnetic null point. The process converts the magnetic energy to plasma kinetic energy through the rearrangement of magnetic field topology. However, it is a non-stationary process and out of the frame of magnetohydrodynamics or electromagnetohydrodynamic. In this work, we present the results of 3D kinetic simulations of the interaction with two ultra-short laser pulses and collisionless plasma.

报告人简介

Yanjun Gu graduated from Fudan University with a Ph.D. in 2013 and worked as a researcher at ELI-Beamlines from 2013 to 2020. From 2021 to 2022 he was Specially Appointed Associate Professor at Institute of Laser Engineering of Osaka University. Now he is working as Associate Professor at SANKEN (Institute of Scientific and Industrial Research), Osaka University. He is mainly engaged in the theories and numerical simulations of laser-plasma interaction. Currently, his main research interests focus on laser plasma-based particle acceleration, radiation and QED effects under strong fields, laboratory astrophysics and the parametric instabilities in LPI.


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