Development of Magnetic Field Control System Using HTS Bulk for ON/OFF Field Switching and Magnetic Field Amplification

High magnetic fields are used in many branches of modern medicine. So, the techniques for magnetic field concentration are very important, and the novel electromagnets and trapped HTS bulk magnets have been fabricated and used in the cell culture and the bulk magnetic drug delivery system. In general, although superconducting magnet can generate high magnetic fields, on/off magnetic switching is impossible because of its large inductance. Therefore, not only the generating of magnetic field but also controlling of magnetic field including on/off switching are very important issues. So, we have been studied the control methods of magnetic field using HTS bulks. In this study, the magnetic field control system consisted of the various shaped HTS bulks and magnetic sources were proposed to achieve the on/off field control and field amplification. The shape of HTS bulk to develop the magnetic control system was optimized by FEM based on analysis, and the abilities of its field switching and amplification were confirmed by experiments. We found that the HTS bulk with slit did control the applied magnetic field, and amplified magnetic fields were obtained at slit parts of HTS bulks.