  We briefly review recent theoretical and simulation studies of charged
colloidal dispersions in alternating electric fields (AC fields). The response
of single colloid to an external field can be characterized by a complex
polarizability, which describes the dielectric properties of the colloid and
its surrounding electrical double layer. We present computer simulation studies
of single spherical colloid, using a coarse-grained mesoscale approach that
accounts in full for hydrodynamic and electrostatic interactions as well as for
thermal fluctuations. We investigate systematically a number of controlling
parameters, such as the amplitude and frequency of the AC-fields. The results
are in good agreement with recent theoretical predictions.
