Low-frequency density fluctuations in the Alcator C tokamak.

CO(2) laser scattering and correlation techniques are used to study turbulent density fluctuations in plasmas in the Alcator C tokamak. These experiments show that the normalized amplitude of the fluctuations n~/n is > 0.1 near the periphery of the plasma. The group velocity of these ~ fluctuations and the dependence on mean plasma density of the spatial distribution of the fluctuations is also studied. The significance of this edge turbulence for plasma heating and current drive by coherent waves is discussed.