Polars:
Evidence for magnetically confined emission
€To
achieve large levels of circular polarisation, radiation process must be
largely cyclotron emission
€For
emission to be in the optical, require high
values of magnetic field strength, ~30 MGauss (~3000 Tesla)
€Expect
this to disrupt the disk
€Eclipse
lightcurves show very sharp (seconds) drops and rises in brightness, consistent with a
small
spot on the white dwarf
€Evidence for magnetically controlled accretion regions
€
HU
Aqr
Bridge et al (2002)