Field and Wave Electromagnetics 2nd Edition by David Cheng

Exercise 6

Consider two coupled circuits, having self-inductances L 1 and L 2 , that carry currents I 1 and I 2 , respectively. The mutual inductance between the circuits is M.
a) Using Eq. (6-161), find the ratio I 1 /I 2 that makes the stored magnetic energy W 2 a minimum.
b) Show that