Experiments were performed using high-power laser pulses
(greater than 50 TW) focused into underdense helium, neon,
or deuterium plasmas (ne
≤ 5 × 1019 cm−3).
Ions having energies greater than 300 keV were measured
to be produced primarily at 90° to the axis of laser
propagation. Ion energies greater than 6 MeV were recorded
from interactions with neon. Spatially resolved pinhole
images of the ion emission were also obtained and were
used to estimate the intensity of the focused radiation
in the interaction region.