Magnetic force is one of the most promising tools to realize a virtual microgravity environment on earth. It has recently been found that the growth of protein crystals might be affected by microgravity owing to the suppression of the convectional flow. We started the development of superconducting magnets to generate uniform and high magnetic force fields to suppress convectional flow. For this purpose, we used a nonlinear programming method. The results obtained clarified that a magnet whose inner coil is longer than the outer one can generate more uniform higher magnetic force fields in a long sample space. A superconducting magnet generating a magnetic force field of 240 T~2/m has already been constructed and tested with NbTi conductors at the Tsukuba Magnet Laboratory. We are constructing a superconducting magnet composed of Nb_3Sn and NbTi conductors to generate uniform magnetic force fields up to 882 T~2/m for next step. We developed a "magnetic force booster" to enhance magnetic force fields generated by superconducting magnets as an alternate method of generating high uniform magnetic force fields. A magnetic force booster consists of rings and disks that are made from ferromagnetic materials and is designed to enhance magnetic force fields without destroying their uniformity. We used a magnetic force booster for a commercial superconducting magnet capable of generating a central magnetic field of 10 T and a magnetic force field of 400 T~2/m in order to observe the booster's performance. The result confirmed that the magnetic force booster could enhance the magnetic force field generated by the magnet to higher than 1360 T~2/m. This result is in good agreement with the analytical result.
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