  SU Uma stars after their long superoutbursts often show single or multiple
rebrightenings. We show how this phenomenon can be understood as repeated
reflections of transition waves which mediate changes between the hot and the
cool state of the accretion disk and travel back and forth in the outer disk
region, leaving an inner part permanently hot. This points to a temporarily
increased viscosity, possibly related to the formation of large-scale and
longer persisting magnetic fields by the dynamo operation during the long
superoutburst. The 'mini-rebrightenings' in the early post-outburst light curve
of V585 Lyr discovered by Kato and Osaki in Kepler observations seem to be
understandable as a small limit cycle of low luminosity changes originating
from a wiggle-feature in the thermal equilibrium curve of the cool optically
thick disk.

Solar and Stellar Astrophysics