An important aspect of the radio emission from galaxy clusters is represented
by the diffuse radio sources associated with the intracluster medium: radio
halos, relics and mini-halos. The radio halos and relics are indicators of
cluster mergers, whereas mini-halos are detected at the center of cooling core
clusters. SKA will dramatically improve the knowledge of these sources, thanks
to the detection of new objects, and to detailed studies of their spectra and
polarized emission. SKA will also provide the opportunity to investigate the
presence of halos produced by radiation scattered by a powerful radio galaxy at
the cluster centers.Comment: 8 pages, 6 figures, to appear in: "Science with the Square Kilometer
Array", eds. C. Carilli & S. Rawlings, New Astronomy Reviews, (Elsevier,
Amsterdam