Electromagnetic Forces and Structural Aspects in Multi-Solenoid Magnets for SMES

摘要

Electromagnetic force among superconducting coils in SMES magnet consisting of multi-solenoid with parallel axes is a serious problem in engineering aspects. Because of very high current density and magnetic field exist inside the coil windings, the mutual reactive force between coils exhibits rather big magnitude that special measures should be taken to fasten each coil into a solid magnet. In this paper, electromagnetic forces among solenoids are numerically calculated based on the derivative of their mutual reactive energy, which equals the product of their mutual inductance by the currents in the coils. Besides, magnet supporting structures is proposed for a Mega-joule SMES magnet, which consists of four solenoids with parallel axes and opposite current directions between adjacent coils.