Beyond the Born and Rytov approximations: A nonlinear approach to electromagnetic scattering

摘要: The Born and Rytov approximations, widely used for solving scattering problems, are of limited utility low-frequency electromagnetic in geophysical applications where conductivity can vary over many orders magnitude. We present four new, relatively simple nonlinear estimators that be rapid modeling. first, termed the static localized approximation, is designed specifically to correct magnitude electric field internal scatterer. second, improves estimate phase scattered includes some cross-polarization effects due full wave scattering. Two further new estimators, based on transformation (the approximations) improve estimation field, especially at high frequency larger size scatterers. Although these approximations functions conductivity, they generally much faster compute than forward problem, almost as efficient or approximations. Moreover, enhanced accuracy has made us optimistic about their application three-dimensional inverse problems electromagnetics. developed this paper will also applicable fields such quantum mechanics, optics, ultrasonics, seismology.