View article

Suprathermal ions, created by fusion reactions or by additional heating, will play an important role in burning plasmas such as the ones in ITER or DEMO. Basic plasma experiments, with easy access for diagnostics and well-controlled plasma scenarios, are particularly suitable to investigate the transport of suprathermal ions in plasma waves and turbulence. Experimental measurements and numerical simulations have revealed that the transport of fast ions in the presence of electrostatic turbulence in the basic plasma toroidal experiment TORPEX is generally non-classical. Namely, the mean-squared radial displacement of the ions does not scale linearly with time, but< r 2 (t)>∼ t γ, with γ≠ 1 generally, γ> 1 corresponding to superdiffusion and γ< 1 to subdiffusion. A generalization of the classical model of diffusion, the so-called fractional Lévy motion, which encompasses power-law (Lévy) statistics for the …