Multi-level Fields

Correlated magnetic structures can be created that produce multiple levels of magnetic fields that enable them to have either attractive or repulsive behaviors depending on their distance apart.  These structures have two (or more) distinct portions (or areas) that are coded differently such that these portions have different near field density and far field density characteristics.   It has been proven that, for a correlated magnetic structure, the near field density increases and the far field density decreases as code density increases.   As such, the designer of correlated magnetic structures can design them such that at least one (short range) portion has a steeper force vs. separation distance curve than another (long range) portion of the structure, which will has a less steep force vs. separation distance curve.  Steep force vs. separation distance curves are called short range field curves and the less steep force vs. separation distance curves are called long range field curves.   There are two distinct combinations of these short range portions and long range portions that have two distinctly different behaviors.  If the short range portion is attractive and the long range portion is repulsive, when the two structures are brought together they will repel each other and then when they reach a certain distance apart will then suddenly attract each other and snap together.  But, if the short range portion is repulsive and the long range portion is attractive, as the two structures are brought together they will attract each other until they reach a certain distance where they will repel each other in which case they will achieve a contactless attachment to each other, whereby the distance corresponds to an equilibrium point between the repulsive and attractive forces.  These multi-level behaviors can be described relative to Fig. 1 which depicts the absolute values of the attractive and repulsive forces of the short range and long range portions of a multi-level correlated magnetic structure. 

Fig. 1 Absolute Values of Attractive and Repulsive Forces of a Multi-level Correlated Magnetic Structure

As can be seen in Fig. 1, the force vs. separation distance curve of the portion of the multi-level correlated magnetic field structure producing a short range field is much steeper than that of the portion producing a long range field.  The short range field curve has much higher peak force but rapidly diminishes to a much lesser force in the far field whereas the long range field curve doesn’t read as high of a peak force but its force diminishes much slower with separation distance such that it is significantly greater in the far field.  The two curves cross at a transition point corresponding to a transition distance apart.  As such, when two multi-level correlated magnetic structures are brought together the long range field portion dominates until the transition point at which time the short range field portion dominates.  So, as previously described, the multi-level structures can be designed so that either a repulsive force will dominate until an attractive force snaps the two structures together or an attractive force will dominate beyond a transition point and a repulsive force within a transition point such that they achieve a contactless attachment.