Concept of Kuster and Toksoz
Schematic diagram of the model composite used in the
non-self-consistent effective medium theory, often called
the ATA, or average T-matrix approximation.
This approach is also due to Kuster and Toksoz
in a geophysical setting.
The true composite is replaced by a large sphere
(dashed circle) containing spherical inclusions of one
of the constituents, while the other serves as the host medium.
The scattering from the pictured composite is set equal to
that from type-* for a spherical scatterer of the size shown.
The composite properties are obtained from the resulting
equations, which turn out to be identical to those for
the Hashin-Shtrikman bounds when the scatterers are spheres,
as we have assumed here.
Concept of the CPA
References