Abstract: Techniques for producing and manipulating magnetic fields. The techniques employ the mutual repulsion of magnetic fields to create uniform magnetic fields and to manipulate the uniform magnetic fields. The uniform magnetic field is created between two planar magnets. The planar magnets have cores which describe a closed curve. Like poles of the electromagnets are connected by the cores. When the electromagnets are activated, repulsion between the magnetic fields generated by the electromagnets creates a magnetic field which extends above and below the planes of the planar magnets. If the planar magnets are positioned parallel to each other and aligned so that the magnetic fields generated by the planar magnets repel each other in the space between the planar magnets, the repulsion between the fields generates a resultant field.

Abstract: Techniques used in systems that employ pairs of coils arranged around an axis to make a magnetic field that rotates around an axis to reduce or eliminate the effects of corners where adjacent ones of the coils meet on the uniformity of the magnetic field. The techniques are particularly useful in plasma reactors that employ magnetically-enhanced reactive ion etching technology. The techniques employ elements that are low cost and may be easily retrofitted to existing plasma reactors. The elements include magnetic shunts that are fitted to the corners of the coils to compensate for the corner effects, trim coils fitted to the corners that, when energized, compensate for the corner effects, and sets of coils that function as 180° coils and thereby reduce the corner effects. The magnetic shunts may be combined with the trim coils.