Patent ID: 6255929
Filing Date: 2001-07-03
Classification: G01R

Abstract:
A method for producing an electromagnet such that the electromagnet is optimized for a predetermined axial magnetic field and predetermined coil region, said method comprising the steps of:a) selecting a predetermined current density value J;b) defining a plurality of target points and a desired axial magnetic field for each target point;c) defining k virtual coils arranged coaxially in the predetermined coil region, where k is an integer greater than 1;d) defining a power expression proportional to the total power dissipation of all the virtual coils, wherein the power expression is proportional to the expression:P.sub.1.vertline.i.sub.1.vertline.+P.sub.2.vertline.i.sub.2.vertline.+P. sub.3.vertline.i.sub.3.vertline.+ . . . +P.sub.k.vertline.i.sub.k,where P is the circumference of each virtual coil and i is the total current in each virtual coil;e) defining an field homogeneity constraint for the maximum magnetic field deviation from the predetermined axial magnetic field for each target point;f) establishing a calculation equivalent to a L.sup.1 -norm minimization calculation wherein the power expression is minimized subject to the constraint of the field homogeneity constraint;g) solving the calculation of step (f) such that the current i for each virtual coil is determined;h) constructing at least one magnet coil for carrying current at a location corresponding to the result of step (f), wherein the magnet coil carries current at the predetermined current density J.