Application of the reaction concept to scattering problems

Rumsey\´s "reaction concept" is applied to scattering problems by considering volume polarization currents which generate the scattered field. The scattering cross section is discussed. Approximation formulas are developed and illustrated by calculations for the echo width of a circular cylinder as a function of dielectric constant. Calculations are made for four plane-wave type trial fields in the cylinder; these are compared with the exact solution and with integral equation solutions through the second order. In this case the reaction method gives better results than the integral equation method, for the same amount of labor.