The Super Tau-Charm Facility (STCF), a high-luminosity electron-positron collider under preliminary research in China, demands high injection efficiency for its injection system. As a key component of the STCF collider ring injection system, the eddy current septum magnet's edge magnetic field uniformity is critical to improving injection efficiency. This paper systematically investigates the rectangular shimming method in traditional pole face shimming and proposes an innovative eddy current enhanced septum plate structure. Simulation results show that it reduces edge magnetic field non-uniformity to less than ±0.1%. The structure is engineering-feasible, offering a new approach for magnetic field optimization of such septum magnets in STCF's injection system.

Eddy current septum magnet,Magnetic field uniformity,Pole face shimming,Septum plate