We present a first attempt to investigate the origin of radio emitting
electrons in the newly discovered class of Mega Radiohalos in clusters of
galaxies. We study the evolution of relativistic electrons accreted by the
external regions of a simulated cluster of galaxy at high resolution, including
the effect of radiative losses and turbulent re-acceleration acting on
relativistic electrons. We conclude that turbulent re-acceleration is enough
prolonged in time to produce a large reservoir of radio emitting electrons in
the large regions illuminated by Mega Radiohalos observed by LOFAR.Comment: 6 pages, 4 figures, submitted to A&A Letter