Intrinsically steady state tokamaks

摘要

It is shown that tokamaks can be intrinsically steady state without seed currents by coupling potato bootstrap current in the region close to the magnetic axis to the banana bootstrap current away from the axis. The equilibria found are highly elongated (e.g. K = 3) and have naturally reversed shear profiles. The vertical instability of elongated tokamaks and the theory of the enhanced reversed shear mode for this class of equilibria are also developed.