A magnetic structure is attached to move with the forcer and has {HEAD ~ a periodic configuration} corresponding to {TAIL ~ the forcer} and in magnetic interchange relation to the platen 
corresponding to
A magnetic structure is attached to move with the forcer and has { HEAD ~ a periodic configuration } corresponding to { TAIL ~ the forcer } and in magnetic interchange relation to the platen
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH