학술논문
Few-femtosecond resolved imaging of laser-driven nanoplasma expansion
Document Type
Working Paper
Author
Peltz, C.; Powell, J. A.; Rupp, P.; Summers, A; Gorkhover, T.; Gallei, M.; Halfpap, I.; Antonsson, E.; Langer, B.; Trallero-Herrero, C.; Graf, C.; Ray, D.; Liu, Q.; Osipov, T.; Bucher, M.; Ferguson, K.; Möller, S.; Zherebtsov, S.; Rolles, D.; Rühl, E.; Coslovich, G.; Coffee, R. N.; Bostedt, C.; Rudenko, A.; Kling, M. F.; Fennel, T.
Source
Subject
Language
Abstract
The free expansion of a planar plasma surface is a fundamental non-equilibrium process relevant for various fields but as-yet experimentally still difficult to capture. The significance of the associated spatiotemporal plasma motion ranges from astrophysics and controlled fusion to laser machining, surface high-harmonic generation, plasma mirrors, and laser-particle acceleration. Here, we show that x-ray coherent diffractive imaging can surpass existing approaches and enables the quantitative real-time analysis of the sudden free expansion of nanoplasmas. For laser-ionized SiO$_2$ nanospheres, we resolve the formation of the emerging nearly self-similar plasma profile evolution and expose the so far inaccessible shell-wise expansion dynamics including the associated startup delay and rarefaction front velocity. Our results establish time-resolved diffractive imaging as an accurate quantitative diagnostic platform for tracing and characterizing plasma expansion and indicate the possibility to resolve various laser-driven processes including shock formation and wave-breaking phenomena with unprecedented resolution.