A ratio, {TAIL ~ Ib/Id} increases with {HEAD ~ a magnetic gradient value}, ∂Hr/∂z to 0.8–0.9 
A ratio , { TAIL ~ Ib / Id } increases with { HEAD ~ a magnetic gradient value } , ∂Hr/∂z to 0.8–0.9
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH