Equilibrium and stability in configurations with three dimensional magnetic axis

The equilibrium and stability of a tube of plasma at a high temperature and with a high density depend on the geometrical shape of the plasma, the magnetic field imposed and the current flowing. However, tubes of plasma can be constructed in equilibrium without a current by employing either a non circular cross section turning along the tube axis (plane stellarators), or configurations twisted in space: this geometrical arrangement was used for the first time by Spitzer with an apparatus having a figure 8 shape in space. The purpose of the studies is to investigate some of the properties of these twisted configurations