Freiburg 2024 – scientific programme
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A: Fachverband Atomphysik
A 23: Atomic Clusters (joint session A/MO)
A 23.6: Talk
Wednesday, March 13, 2024, 15:45–16:00, HS 1015
Reconstructing the anisotropic expansion of a laser driven nanoplasma — •Paul Tuemmler1, Felix Gerke2, Christian Peltz1, Hendrik Tackenberg1, Björn Kruse1, Bernhard Wassermann2, Thomas Fennel1, and Eckart Rühl2 — 1University of Rostock, D-18059 Rostock, Germany — 2Freie Universität Berlin, D-14195 Berlin, Germany
Coherent diffractive imaging (CDI) at X-ray free-electron lasers (FELs) has evolved into a well-established method for the structural investigation of unsupported nanoparticles. This inherently static method can be readily adopted to time-dependent studies by incorporating a second pulse in a pump-probe scheme.
In a recent experiment at LCLS, we utilized this method to study the fundamental process of free plasma expansion into vacuum using the example of laser-pumped SiO2 nanospheres. The resulting plasma expansion rapidly and isotropically softens the initial surface density step. This, in turn, increases the radial decay of the scattering signal eventually precluding meaningful measurements due to a diminishing signal-to-noise ratio within only a few hundred femtoseconds [1].
Here, we present the results of a follow-up experiment at the European XFEL where we revisited SiO2 as a target, but operated in a weaker excitation regime. This approach allowed us to record images over far longer timescales and revealed a strong anisotropic expansion dynamic, as predicted by theory [2].
[1] C. Peltz et al., New J. Phys. 24, 043024 (2022).
[2] C. Peltz et al., Phys. Rev. Lett. 113, 133401 (2014).
Keywords: coherent diffractive imaging (CDI); European X-ray free-electron laser (EU-XFEL); strong-field induced dynamics; plasma expansion into vacuum; model-based reconstruction