Effect of drift modes on currentfree plasma transport processes in a stellarator

Abstract

The authors measure the losses of charged particles and heat via the electrons in the toroidal ℓ = 3 Saturn stellarator with large shear (θmax ≲ 0.25). From an analysis of the relationships derived they conclude that the pseudoclassical nature of the energy losses observed is due to the presence of drift modes in the plasma. The particle losses for shear θ < 0.05 are determined by the turbulence of the plasma, whereas at θ > 0.05 the diffusion both in magnitude and functional dependence matches the neoclassical theory.