Transient Eddy current distribution in cylindrical shells

Axial currents in the form of step functions or pulses flowing in a filament parallel to and inside a cylindrical shell of infinite length and finite thickness, give rise to eddy currents in the conducting material of the shell due to proximity effect. Similar currents returning through the shell give rise to skin effect. The distribution of both these types of currents is determined analytically by solving the differential equation for penetration of currents in the conducting material in the transient state and appropriately applying boundary conditions. The associated loss is also determined. Constant permeability is assumed.