Effects of turbulence on radiative properties of tokamak edge plasmas

Abstract

The effect of turbulent temperature fluctuations on the radiative losses in tokamak edge and divertor plasmas is investigated. A statistical model is developed. The formalism involves both the probability density function of the fluid quantities and the expression of the emitting energy level population in terms of these quantities. We apply the statistical model to calculations of radiative power losses, successively for lithium and hydrogen radiation. In the former case, the energy level populations are obtained with an analytical collisional-radiative model accounting for non-coronal and transport effects. In the hydrogen case, the emitting level population is calculated by a collisional-radiative code. The role of electron temperature fluctuations is discussed in detail. Application to hydrogen line radiation in JET conditions reveals the significant role of turbulence in the repartition of the radiated energy inside the divertor. (c) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei