  The irradiation of few nm thick targets by a finite-contrast high-intensity
short-pulse laser results in a strong pre-expansion of these targets at the
arrival time of the main pulse. The targets decompress to near and lower than
critical densities plasmas extending over few micrometers, i.e. multiple
wavelengths. The interaction of the main pulse with such a highly localized but
inhomogeneous target leads to the generation of a short channel and further
self-focusing of the laser beam. Experiments at the GHOST laser system at UT
Austin using such targets measured non-Maxwellian, peaked electron distribution
with large bunch charge and high electron density in the laser propagation
direction. These results are reproduced in 2D PIC simulations using the EPOCH
code, identifying Direct Laser Acceleration (DLA) as the responsible mechanism.
This is the first time that DLA has been observed to produce peaked spectra as
opposed to broad, maxwellian spectra observed in earlier experiments. This
high-density electrons have potential applications as injector beams for a
further wakefield acceleration stage as well as for pump-probe applications.
