Patent ID: 8179220

Claim:
A method of producing a magnetic field having a controllable magnitude and direction within a field space; said method comprising: defining two orthogonal field components wherein a first field component is to be generated along a first longitudinal axis and a second field component is to be generated along a second longitudinal axis; positioning a plurality of pole faces at locations along each of the first and second longitudinal axes; and for each of the two orthogonal field components: selecting a first magnetostatic potential to apply to a first plurality of longitudinal pole faces at a first longitudinal boundary oriented substantially normal to a longitudinal axis; selecting a second magnetostatic potential to apply to a second plurality of longitudinal pole faces at a second longitudinal boundary oriented substantially normal to the longitudinal axis; identifying a plurality of lateral pole faces disposed along a lateral boundary intermediate the first and second longitudinal boundaries; each respective one of the plurality of lateral pole faces disposed in a respective lateral boundary plane oriented substantially normal to the longitudinal axis; and for each respective one of the plurality of lateral pole faces, selecting a value of a respective magnetostatic potential in accordance with a position of the respective lateral boundary plane relative to the first and second longitudinal boundaries; and supplying selected values of magnetostatic potential to each of the plurality of pole faces; thereby creating a substantially uniform magnetic field that is controllable in magnitude and direction within the field space.