Editing Halbach array (section)

===Variable linear arrays===

[[File:HalbachArraySchematic1.png|thumb|Schematic of a Halbach array consisting of a series magnetized rods|220x220px]]
[[File:HalbachArraySchematic2.png|thumb|Equal-gearing arrangement for a variable Halbach array|220x220px]]
A series of magnetic rods, magnetized perpendicular to their axes, can be arranged into a Halbach array. If each rod is then rotated alternately through 90°, the resultant field moves from one side of plane of the rods to the other, as shown schematically in the figure.

This arrangement allows the field to effectively be turned on and off above or below the plane of the rods, depending on the rotation of the rods. Such a device makes an efficient mechanical magnetic latch requiring no power. A detailed study of this arrangement has shown that each rod becomes a subject to a strong torque from its neighboring rods when rotated.<ref name="Hilton2012"/> However, a simple and efficient solution, providing both stabilization and the ability to rotate each rod alternately, is simply to provide an equal-gearing arrangement on each rod, as shown in the figure.
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