Characterization of plasma and laser conditions for single hot spot experiments

The TRIDENT laser system at the Los Alamos National Laboratory is being use d 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 spatia l smoothing of laser beams. A long scale length, hot plasma (similar to 1 m m, similar to 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 10(14)-10(16) W/cm(2). The plasma densi ty, temperature, and flow profiles are measured using a gated imaging spect roscopy of collective Thomson scattering from the heater beam. Results of t he laser and plasma characterization, and initial results of backscattered: SRS, SBS, and beam steering in a flowing plasma are presented.