Generation and Confinement of Uniform Magnetic Field Using Second-Generation Superconducting Racetrack Coils

Advancement in a cryogen-free superconducting magnet is addressed in this paper. In the proposed laboratory-sized magnet configuration, the racetrack coils are arranged as central coils to provide the majority of required magnetic field and side coils that are responsible not only to lessen the stray fields but also to improve the homogeneity of the magnetic field in the region of uniformity. The main advantage of implementing racetrack coils over solenoid coils is the ability to generate a highly uniform field for either long specimens or using several samples simultaneously. Moreover, an optimization technique with the objective of minimizing nonuniformity of magnetic field with respect to magnetic and mechanical constraints is carried out. Because of considerable numbers of designing variables, coils' locations, and their associated currents, the problem is initially solved in 2-D Cartesian coordinates. Consequently, in order to ascertain the accuracy of the solution achieved from the 2-D model, a 3-D model based on the optimized variables is studied and the results are discussed.