FTU is a compact, high-magnetic-field tokamak constructed along the line of the ALCATOR experiments at MIT and of the FT (Frascati Tokamak) experiment in Frascati. The compact, high magnetic field devices are characterized by a large current density value
with B being the toroidal magnetic field intensity and R the major radius.
with Paux being the auxiliary heating power. Thus, the combination of large B values and small dimension allows the achievement of large j values. This, in turn, has several advantages:
where the plasma resistivity depends on the plasma temperature. Thus, the plasma can be heated up to relatively high temperatures without the need of strong auxiliary heating systems.
Thus, compact, high field experiments can easily reach high values of the particle density.
FTU has begun operation with plasma in 1990, and is still producing good physics results. It has achieved its design parameters: 1.6 MA at 8 T, and plasma density larger than 3e20 m-3. FTU is provided with three additional heating systems (LH, ECRH and IBW), two pellect injection systems, one shooting along the major radius and one shooting along a vertical chord in the high field region and of course a complete set of plasma diagnostics.