Laser-dust interaction and dust size distribution measurements on DIII-D

Abstract

The determination of dust radius distributions from the measurement of laser scattering intensity in tokamaks is presented. The analysis takes into account non-Rayleigh regimes of light scattering for different complex refractive indices of dust materials, as well as dust evaporation due to heating by laser radiation. The model is applied to calculate the dust particle radius distribution in tokamaks during normal plasma operation. It is shown that a relatively small amount of large dust particles in the distribution may play a significant role for estimation of the dust mass inventory in tokamaks. © 2007 American Institute of Physics.