Speaker
Description
The advent of the first X-ray free-electron lasers (XFELs), FLASH in 2004 and LCLS in 2009, may prove to be the most profound development since the invention of the laser and, equally, the synchrotron. Sharp improvements in a number of laser parameters, most notably intensity and pulse duration, support this expectation. This brings scientific dreams within reach. Indeed, the unprecedented opportunities and expectations have triggered considerable research activities worldwide. In my talk, I will give an overview of the experimental application of the European XFEL to explore relativistic laser plasma interactions, warm dense matter, materials in extreme conditions, and laboratory astrophysics.
Since May 2019, the High Energy Density Science (HED) instrument at the European X-ray Free-Electron Laser Facility in Schenefeld, Germany, allows international users to investigate a wide range of materials and systems at extreme conditions [1]. European XFEL and the HIBEF user consortium [2] form a joint group of more than 30 people for HED research, development and user operation.
To drive a sample from ambient conditions to extreme excitations, a variety of high energy drivers are available. Besides a dedicated platform for diamond-anvil cell research [6], we have three separate optical laser systems for warm- to hot-dense-matter creation, dynamic compression [3] and laser-plasma interaction in electron-relativistic regime [4]. These drivers allow studying various phase space parameters with time-resolution down to 10 fs, pressures into the TPa regime [5], and electric field strength up to 1021 W/cm, both at surfaces and in the bulk.
The unique HED instrument allows to study these systems with precise ultrafast x-ray probes including spectroscopy [7], x-ray diffraction, small- and wide-angle scattering as well as phase contrast imaging methods. It is fully tuneable in the photon energy range from 5 to 25 keV at different bandwidths, can be focused to a variety of diameters.
The talk will go into further detail about diagnosing HED plasmas with diffraction, emission and energy-loss spectroscopy (inelastic x-ray scattering) from phonon modes and ion-acoustic waves, and x-ray Talbot imaging.
[1] U. Zastrau, et al., J. Synchrotron Rad. (2021). 28, 1393-1416
[2] www.hibef.de
[3] McMahon and Zastrau, DOI: 10.22003/XFEL.EU-TR-2017-001
[4] Laso Garcia et al., High Power Laser Science and Engineering, 1.5 (2021)
[5] Descamps et al., Rev. Sci. Instrum. 96 (7), 075206 (2025)
[6] Liermann et al., J. Synchrotron Rad. (2021). 28, 688-706
[7] Preston, Goede et al., Journal of Instrumentation, Volume 15 (2020)
