The TRIDENT laser system at the Los Alamos National
Laboratory is being used for fundamental experiments which
study the interaction of self-focusing, stimulated Raman
scattering (SRS) and stimulated Brillouin scattering (SBS)
in a near-diffraction-limited (single) laser hot spot in
order to better understand the coupling between these plasma
instabilities. The diffraction limited beam mimics a single
hot spot found in speckle distributions that are typical
of random or kinoform phase plates (RPP or KPP) used for
spatial smoothing of laser beams. A long scale length,
hot plasma (∼1 mm, ∼0.6 keV) is created by a separate
heater beam, and the single hot spot beam is used to drive
parametric instabilities. The focal plane distribution
and wave-front of the interaction beam are characterized,
and its intensity can be varied between 1014–1016
W/cm2. The plasma density, temperature, and
flow profiles are measured using a gated imaging spectroscopy
of collective Thomson scattering from the heater beam.
Results of the laser and plasma characterization, and initial
results of backscattered SRS, SBS, and beam steering in
a flowing plasma are presented.