  Wickramasinghe et al. (2014) and Briggs et al. (2015) have proposed that the
strong magnetic fields observed in some single white dwarfs (MWDs) are formed
by a dynamo driven by differential rotation when two stars, the more massive
one with a degenerate core, merge during common envelope (CE) evolution
(Ferrario et al., 2015b). We synthesize a population of binaries to investigate
if fields in the magnetic cataclysmic variables (MCVs) may also originate
during stellar interaction in the CE phase.
