Error field analysis of steady state tokamak reactor with ferromagnetic (F82H) blanket

Error fields generated by a ferromagnetic steel (reduced activation ferritic steel: F82H) blanket were estimated in a conceptual design of the steady state tokamak reactor. The amplitude of radial error field with the poloidal mode number=2 and the toroidal mode number=1 (/spl Delta/B/sub r21/), which results in locked mode disruptions, was about 0.4 G at the plasma surface, while the maximum radial error field was about 600 G at the port edges. The relative error field (/spl Delta/B/sub r21//B/sub T//spl ap/4.5/spl times/10/sup -6/ where B/sub T/ is the toroidal field of 9T) was comparable with the predicted critical relative error field for locked modes.