P. Neumayer,
B. Aurand,
R. Fraga,
B. Ecker,
R. E. Grisenti,
A. Gumberidze,
D. C. Hochhaus,
A. Kalinin,
M.C. Kaluza,
T. Kühl,
J. Polz,
R. Reuschl,
T. Stöhlker,
D. Winters,
N. Winters,
and Z. Yin
Evidence for ultra-fast heating in intense-laser irradiated reduced-mass targets
Phys. Plasmas, 19 :122708 (December 2012)
Evidence for ultra-fast heating in intense-laser irradiated reduced-mass targets
Phys. Plasmas, 19 :122708 (December 2012)
Abstract:
We report on an experiment irradiating individual argon droplets of 20 μm diameter with laser pulses of several Joule energy at intensities of 10^19 W/cm^2. K-shell emission spectroscopy was employed to determine the hot electron energy fraction and the time-integrated charge-state distribution. Spectral fitting indicates that bulk temperatures up to 160 eV are reached. Modelling of the hot-electron relaxation and generation of K-shell emission with collisional hot-electron stopping only is incompatible with the experimental results, and the data suggest an additional ultra-fast (sub-ps) heating contribution. For example, including resistive heating in the modelling yields a much better agreement with the observed final bulk temperature and qualitatively reproduces the observed charge state distribution.