A new target field method for optimizing longitudinal gradient coils' property

A new approach has been presented in the paper to optimize the longitudinal gradient coil performance. First, traditional spherical harmonic target field method is deduced, the relation between the magnetic field and the current distribution is described by a matrix equation. Then, simulated annealing method is introduced to the optimization procedure, and those high order coefficients which are used to vanish become the variables designed for optimization. Finally, stream function method is used to transform the current density into discrete gradient coils. Comparison between traditional method and the optimized method shows that the in-homogeneity in the region of interest can be reduced from 13.59% to 4.9%, the coil efficiency is increased from 11.56mT/m/A to 18.07mT/m/A, and the minimum distance of the discrete current wire is raised from 0.95mm. to 2.02mm.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000246922600317&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Engineering, Electrical & ElectronicCPCI-S(ISTP)