Title: Remarks on the polarization tensor of a composite medium containing close or touching disks


				Eric Bonnetier
                     LMC--IMAG, Universite Joseph Fourier,
                         BP 53, 38041 Grenoble Cedex 9
                         Email: Eric.Bonnetier@imag.fr
                 Web page: http://www-lmc.imag.fr/EDP/edp.html


Abstract:
We consider a composite medium, made of circular conducting inclusions of 
small diameter $\varepsilon$ embedded in a homogeneous matrix phase, 
when the inhomogeneities are strongly interacting, i.e., when they are very 
close or even touching.
The asymptotics of the potential involve a polarization tensor that can be 
expressed as a series in terms of the inter--inclusion distance and the 
conductivity contrast. The gradient between the inclusions has a similar
series representation. We study their singular limits as the inter--inclusion
distance goes 0.