Rayleigh Scattering from Excited Atoms in Plasmas

Rayleigh and resonance scattering allow spatially resolved measurements of the neutral density and temperature in a plasma. While resonance scattering often is disturbed by line radiation of the plasma, this can be overcome by observation of near-resonant Rayleigh scattering. We performed scattering experiments at the 587.6-nm helium line using a flashlamp-pumped dye laser. The spectral dependence of the Rayleigh cross section and the polarization of the scattered light agree with theory.