Unlike
tokamaks, stellarators can in principle operate in continuous
mode: In a stellarator, the spiralling of the field lines around the
torus axis is achieved solely by means of external coils. A stellerator
can thus dispense with a longitudinal current in the plasma and hence
with a transformer. It is thus basically capable of working in steady
state.
The Wendelstein experiments of IPP are investigating whether
stellarators could provide the technically simpler solution for a fusion
power plant.