Field-free line formation in a magnetic field

In this communication, the theory of field-free line (FFL) formation in a magnetic field is investigated. It is shown that an FFL can be generated by only three Maxwell coil pairs. By varying the applied currents, the FFL can be arbitrarily rotated, while keeping the coils static in space. For translation, additional Helmholtz coil pairs can be used. These findings enable efficient realization of a field generating unit for a recently developed imaging method named magnetic particle imaging.