Particle transport in the Frascati Tokamak upgrade

Three methods of density modulation have been used in FTU discharges (gas puffing, pellet injection and current rampup). The analysis of particle balance confirms that the neoclassical theory is not adequate and the experimental results obtained by the three methods are used to verify the validity of an empirical expression for the radial particle flux. Such an expression is relevant for the design of future experiments and constitutes a constraint for any satisfactory theory.