Strength considerations on the magnetic field coils of the Spanish Stellarator TJ-II

TJ-II is a medium size stellarator of the heliac-type under construction in Madrid, Spain. The basic data of this device are: average major plasma radius R/sub 0/=1.5 m; minor plasma radius a=0.1 to 0.2 m; toroidal magnetic field on the axis B/sub 0/=1 T. Detailed structural analyses have been performed for the Toroidal Field System and the so-called Hard Core, which comprises three coil systems, because of the high stresses and deformations expected for these complicated compound structures. The paper deals with these analyses, the results and the consequences for the design and operation of the coil systems.