FULL APERTURE BACKSCATTER STATION IMAGER DIAGNOSTICS SYSTEM FOR FAR-FIELD IMAGING OF LASER-PLASMA INSTABILITIES ON NOVA

In ICF, the understanding of laser plasma scattering processes is esse ntial for laser target coupling and for controlling the symmetry of in direct drive implosions. The existing Nova full aperture backscatter s tation has been useful in understanding laser plasma instabilities occ urring in hohlraums by measuring the quantity, spectral distribution, and near-field spatial distributions of Brillouin and more recently Ra man backscatter. Equally important is an understanding of the far-fiel d spatial intensity distribution which could help in understanding fil amentation, threshold and saturation processes. This article describes a broadband, color-corrected far-field imager and associated diagnost ics capable of imaging the source of scattered light to better than 25 mu m resolution. Brillouin and Raman backscatter can be imaged throug h the Nova beam-7 focusing lens or the imager can be used Like a micro scope to image side scatter from other beams. (C) 1997 American Instit ute of Physics.