The FTU-D project

A modification of the FTU tokamak (toroidal field BT=8T, plasma current IP=1.6MA, minor radius a=0.3m, major radius R=0.93m) is proposed in order to extend the FTU operation to strongly shaped plasmas (FTU-D: R=1m, a=0.18-0.2m, elongation κ=1.6, triangularity δ up to δ=0.8). FTU has a circular vacuum vessel and was built to produce circular plasmas, however unbalancing the currents in the windings of the air core transformer a plasma shaping can be produced. Single Null (SN) and Double Null (DN) equilibria have been studied with a maximum current in the range 0.350-0.450 MA. The scientific aim of the project is the investigation of the advanced tokamak operation, characterised by the simultaneous achievement of high βN (normalised beta) and high bootstrap current fraction (fB) in regimes with high-energy confinement obtained by current and pressure profile control. The main features of FTU-D, with respect to other existing tokamaks, are the high magnetic field (BT=5-2.5T), the high density and aspect ratio value (A=R/a=5-6) and the possibility of investigating regimes with dominant electron heating. (author)