Wickramasinghe, DayalFerrario, Lilia2015-12-131387-6473http://hdl.handle.net/1885/90868Detailed spectroscopic studies of the magnetic white dwarfs in the AM Herculis type systems have shown that in most systems the magnetic white dwarf has two dominant poles with field strengths that differ by a factor ~1.5-2 indicating non dipolar field structures. In all but the highest field system AR UMa, phase locking appears to be maintained through magneto-static interactions between the magnetic field of the white dwarf and the dynamo generated magnetic field of the secondary star.20002015-12-12