Characteristic X-rays generated by high-intensity laser
interaction with solids were investigated and used for
determining the resulting hot electron populations. Spectrally
as well as spatially resolved data are evaluated for this
purpose. The experimental data were compared with Monte
Carlo simulations to determine the electron energy distribution
and geometric features of the electron beam. These results
are in good agreement with PIC simulations. The self-generated
low-resistivity channel of the electron beam results in
a distinct difference in the generated rear-side X-ray
spot when the electron beam propagates in an insulator
rather than a metal. Self-generated electric fields prevent
electron propagation into the vacuum. This fact is used
for demonstrating photopumping of cobalt with copper
Kα radiation, an experiment relevant
to innershell X-ray laser schemes. The emission of cobalt
is compared with that of nickel, which is not photopumped
by copper Kα, and is found to be
enhanced by a factor of 2.5.
Coherent transition radiation from attosecond electron pulses