Improved halbach magnets by particle swarm optimization for mobile nuclear magnetic resonance systems

The Halbach magnets have been widely used in engineering especially for the mobile NMR (Nuclear Magnetic Resonance) systems. The homogeneity of the magnetic field generated by the magnet affects the imaging quality of NMR. In this paper, we have proposed two improved 2D constructions of the Halbach magnet, which can improve the magnetic field uniformity greatly. The improved constructions of Halbach magnet are optimized by the modified PSO (particle swarm optimization) algorithm and the simulations are based on the 2D Finite Element Method (FEM) analysis