The Effects of Conductor Magnetization on the Magnetic Field on an Accelerator Magnet System With Various Conductors

It has been over fifty years since the first papers on the effects of superconductor magnetization on magnet field quality were measured. The effects of conductor magnetization are most pronounced at low fields. By 1972, a reliable method for estimating the effects of conductor magnetization on the field quality in accelerator magnets been developed. This method is presented in this paper. The model includes unsaturated iron. The effect of filament proximity was added to the model in the 1980s. A simple passive in-magnet correction system was demonstrated in the early 1990s. The problem that remained was the effect of strand-to-strand circulating currents in magnet cables. These currents decay with time for magnets made with cables made with any conductor. Accelerator magnets made with wide REBCO tapes in place of cables can be expected to exhibit magnetization current decay due to flux creep. Can the calculation methods in use before 1990 lead to solutions for reducing the effects of conductor magnetization in HTS magnets as well as LTS magnets? This will be discussed in this paper.