Study on the Magnetic Forces of the Dipole in the SPERF

The Space Plasma Environment Research Facility (SPERF) in Harbin, China, is a user facility dedicated to studying space plasma physics on ground. Magnetic forces are critical to the reliable operation of a magnetic system. A dipole magnet plays a central role in the system and its force conditions are extremely complicated. So, the magnetic force of the dipole magnet is studied in this article. The magnetic system is first introduced. Then, the virtual work principle is presented to evaluate the force analytically. Not dedicated to the complex analytical computation, the qualitative analysis is done based on the breaking of the symmetry of the system from the perspective of the dipole. To validate the qualitative results and solve the force precisely, the finite-element analysis in ANSYS Maxwell is performed. The force results are analyzed and regular patterns are obtained. The influence of the spatial position and the eddy current are studied. In a complex system, the dipole forces from different source magnets compete to dominate as the time proceeds. The methods for analyzing the magnetic forces can easily be extended to other electromagnetic systems.