报告人：Dr. Lingen Huang, Helmholtz-Zentrum Dresden-Rossendorf

会议时间：2024年5月29日（周三）上午10:30

会议地点：清河路390号19号楼四楼会议室

报告内容：

The recent commissioning of novel large-scale experimental pump-probe platforms equipped with both optical high power lasers and brilliant X-ray free electron lasers (XFELs), such as the European XFEL-HED/HiBEF, LCLS-MEC and SACLA beamlines, provide unprecedented opportunities for experimental studies to investigate the high energy density (HED) physics and strong-field quantum electrodynamics (QED). In this talk, we will present our latest experimental results of HED sciences driven by a 3J/30fs/100 TW ReLaX laser performed at European XFEL-HED/HiBEF station. By fielding multiple X-ray diagnostics of small angle X-ray scattering (SAXS), X-ray phase contrast imaging (XPCI) and X-ray emission spectroscopy (XES) simultaneously, we are able to investigate the multi-scale spatio-temporal processes launched by the electron transport ranging from few tens of femtoseconds (fs) to hundreds of picoseconds (ps). Specifically, we have measured the plasma expansion and filamentation during the pre- and intra-short-laser-pulse solid interactions indicated by the time resolved SAXS with ~10 nm spatial resolution. Furthermore, the resonant XES reveals the ultra-fast atomic processes such as ionization and recombination dynamics for a selected highly ionized charge state of Cu with a lifetime of up to ∼10 ps in the hot dense conditions above 500 eV. In particular, a spherical divergent shock originating from the interaction region directly driven by the laser ablation, and a cylindrical convergent shock originated from the wire edges beyond 100 μm off the focal position driven by the lateral transient surface return current, are clearly observed from 10s of ps to 1 ns using the X-ray phase contrast imaging(XPCI). Such cylindrical shock wave travelsling towards the wire core, is predicted to compress the mass density with a factor of 9 and generate the pressures nearly 1 Gbar (100 TPa) by the Joule-class femtosecond pulse laser laser, offering an alternative to the nanosecond kJ laser pulse-driven and pulse power Z-pinch compression methods to study the high-pressure physics. The combination of techniques constitute a promising avenue to enable deeper insights into benchmarking the simulation codes and understanding laser-driven ion acceleration, planetary science and fusion energy research.

报告人简介：

Dr. Lingen Huang received his PhD degree at Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences (CAS) in 2013. At present, he is a tenured staff scientist at the high energy density division, Helmholtz-Zentrum Dresden-Rossendorf (HZDR). His researches focus on understanding the ultrafast dynamics of high energy density plasmas driven by the ultra-short relativistic high power lasers at extreme conditions, via high performance computational simulations, as well as large scale pump-probe experiments combining unique light sources with optical Petawatt (PW) high power lasers and X-Ray free electron lasers (XFELs). He also has interest to study the warm dense matters heated and compressed by the high energy nanosecond lasers or XFELs. He has participated and led many user experimental beamtimes at American LCLS-MEC, Japanese SACLA and recently European XFEL-HED beam stations as the participant and also as the main/principle investigator.