A DOUBLED ND-GLASS LASER SYSTEM FOR INCOHERENT THOMSON SCATTERING FROM LOW DENSITY PLASMAS

摘要

Conventional Thomson scattering using a ruby laser evidencesndifficulty in scattered signal detection as electron densities drop below 1013 cm﹣³ . Studies of plasmas of interest, such as θ-pinch endloss flow, can require density resolution in that range. Use of a Nd-Glass Laser as a source and frequency doubling the output can result in increases in the incident energy and quantum efficiency of the detectors such that gains in scattered signal of greater than an order of magnitude over a conventional ruby laser system can be achieved. Due to the ~25A bandwidth of the Nd-Glass Laser line, however, the electron temperature information in the incoherent scattered signal must be extracted from a Voight Profile, not from the usual Gaussian profile as when a ruby laser is used.