磁偶极子 ●电流环的磁感应强度： B=V×A Pxmx产 3=V黄×(m×)+3V×(mX剂 Fx(mx)+m(.F)-(m)] 3 [mr·)-(mF刃+(3m-m) 53(m)F-r2m列 B=6[3(ma)a,-m] lexu@mall.xidian.edu.cnlexu@mail.xidian.edu.cn 8 磁偶极子  电流环的磁感应强度： B A =∇×   33 3 5 3 5 3 2 5 1 1 () () 3 1 ( ) [ ( ) ( )] 3 1 [ ( ) ( )] (3 ) 1 [3( ) ] m r mr mr rr r r mr m r m r r r mr r rmr m m r r mrr rm r × ∇× =∇ × × + ∇× × = − × × + ∇⋅ − ⋅∇ =− ⋅ − ⋅ + − = ⋅−                   0 3 [3( ) ] ˆˆ 4 B ma a m r r r µ π = ⋅−    XIDIAN UNIVERSITY LEXU@MAIL.XIDIAN.EDU.CN