In the magnet 36 shown in FIG 3, the magnetic pole pieces 38a, 38b, and 38c are symmetrically arranged around channel 34 using permanently magnetizable iron or the like with individual coils wrapped around {HEAD ~ each pole piece}, as shown by {TAIL ~ coils} 40a, 40b and 40c, to initially magnetize each of the pole pieces to a desired permanent magnetization 
In the magnet 36 shown in FIG 3 , the magnetic pole pieces 38a , 38b , and 38c are symmetrically arranged around channel 34 using permanently magnetizable iron or the like with individual coils wrapped around { HEAD ~ each pole piece } , as shown by { TAIL ~ coils } 40a , 40b and 40c , to initially magnetize each of the pole pieces to a desired permanent magnetization
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