The magnetic core 30 has {HEAD ~ a core length lm} and the coil 24 has a coil length {TAIL ~ lc} less than the core length lm 
The magnetic core 30 has { HEAD ~ a core length lm } and the coil 24 has a coil length { TAIL ~ lc } less than the core length lm
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH