Development of superconducting magnets for uniform and high magnetic force field generation

Magnetic force is one of the most promising tools to realize a virtual microgravity environment on Earth. It has been found that the growth of protein crystals might be affected by microgravity. The reason for this influence appears to be the suppression of the convectional flow. We are developing superconducting magnets to generate spatially uniform and high magnetic force fields that will suppress the convectional flow. We have completed a design for a superconducting magnet that is composed of Nb₃Sn and NbTi conductors. This magnet is designed to generate spatially uniform magnetic force fields up to 860 T²/m. The design was carried out using a method of nonlinear programming. The error of the axial component of the magnetic force fields is less than 1%, and the error of the radial ones is less than 2%. The central magnetic field of this magnet is 17 T at the operating current. We identified this magnet as Prototype II because the Prototype I, which had been constructed in 1998, was constructed with only NbTi conductors. Furthermore, it generates a magnetic force field of 240 T²/m and has a central magnetic field of 9 T, had been constructed in 1998. Prototype II will be cooled down below 4.5 K by two GM cryocoolers.