TY  - JOUR
AU  - Vinko, Sam
AU  - Vozda, Vojtech
AU  - Andreasson, Jakob
AU  - Bajt, S.
AU  - Bielecki, Johan
AU  - Burian, Tomas
AU  - Chalupsky, Jaromir
AU  - Ciricosta, Orlando
AU  - Desjarlais, M. P.
AU  - Fleckenstein, H.
AU  - Hajdu, Janos
AU  - Hajkova, Vera
AU  - Hollebon, Patrick
AU  - Juha, Libor
AU  - Kasim, M. F.
AU  - McBride, E. E.
AU  - Muehlig, Kerstin
AU  - Preston, T. R.
AU  - Rackstraw, D. S.
AU  - Roling, Sebastian
AU  - Toleikis, S.
AU  - Wark, Justin
AU  - Zacharias, Helmut
TI  - Time-Resolved XUV Opacity Measurements of Warm Dense Aluminum
JO  - Physical review letters
VL  - 124
IS  - 22
SN  - 1079-7114
CY  - College Park, Md.
PB  - APS
M1  - PUBDB-2020-02737
SP  - 225002
PY  - 2020
AB  - The free-free opacity in plasmas is fundamental to our understanding of energy transport in stellar interiors and for inertial confinement fusion research. However, theoretical predictions in the challenging dense plasma regime are conflicting and there is a dearth of accurate experimental data to allow for direct model validation. Here we present time-resolved transmission measurements in solid-density Al heated by an XUV free-electron laser. We use a novel functional optimization approach to extract the temperature-dependent absorption coefficient directly from an oversampled pool of single-shot measurements, and find a pronounced enhancement of the opacity as the plasma is heated to temperatures of order of the Fermi energy. Plasma heating and opacity enhancement are observed on ultrafast timescales, within the duration of the femtosecond XUV pulse. We attribute further rises in the opacity on ps timescales to melt and the formation of warm dense matter.
LB  - PUB:(DE-HGF)16
C6  - pmid:32567902
UR  - <Go to ISI:>//WOS:000537620500007
DO  - DOI:10.1103/PhysRevLett.124.225002
UR  - https://bib-pubdb1.desy.de/record/441818
ER  -