Confinement of high temperature plasmas

A high temperature plasma is magnetically confined without leaks or cusps in a smooth toroidal configuration by tangential magnetic field lines on its surface which have a zero rotation number, and include a selected finite even non-zero number of closed toroidal magnetic field lines, which are limit cycles in the sense that all other surface field lines are asympototic to neighboring pairs of these closed field lines, and the poloidal cross-section of the plasma is non-convex. The resulting unique structure makes the confined plasma relatively insensitive to approximations, tolerances, and variations in the parameters of design, construction and operation. Furthermore, use of the sense of averaging appropriate to evaluation of interchange instabilities shows that the resulting magnetic bottle is an optimal toroidal magnetic well