Analytical model of a travelling wave multipole field electromagnetic launcher

The problem of the evaluation of eddy currents induced in a conductive cylinder is here reconsidered under the light of possible application in the electromagnetic launch context. In particular we derive an analytical solution when the system is excited by a sinusoidal current flowing on a saddle coil moving in the axial direction. Subsequently we consider an arrangement of such coils distributed in the axial and azimuth direction. When properly fed they produce a travelling wave of flux distribution which is able to exert a thrust force on the conductive cylinder. Since the governing vector field equation is not separable in the cylindrical coordinate, an approach based on the second order vector potential (SOVP) formulation has been here adopted. Scalar field equations are obtained whose solutions are expressed in terms of Bessels function.