Electromagnetic Design of HTS Insert for Ultrahigh Field NMR Magnet

In this paper, an electromagnetic design of a 27 T nuclear magnetic resonance (NMR) magnet composed of a low-temperature superconducting outsert magnet and a high-temperature superconducting (HTS) insert magnet is carried out. An optimization code is improved according to the fabrication form of the HTS magnet. Concerns about the radial magnetic field, the hoop stress, the current margin, length of tape used, and outer diameter of the HTS insert are investigated with respect to the magnet length, inner radius, and current density. The screening current effect is taken into consideration for the sensitivity analysis. The results predict that the larger the inner radius of the HTS insert, the better the real field homogeneity can be obtained. Screening current effect can deteriorate the field homogeneity zonally by about 1 order of magnitude.