Jr. Murray et al., The effects of tidally induced disc structure on white dwarf accretion in intermediate polars, M NOT R AST, 302(1), 1999, pp. 189-196
We investigate the effects of tidally induced asymmetric disc structure on
accretion on to the white dwarf in intermediate polars. Using numerical sim
ulation, we show that it is possible for tidally induced spiral waves to pr
opagate sufficiently far into the disc of an intermediate polar that accret
ion on to the central white dwarf could be modulated as a result. We sugges
t that accretion from the resulting asymmetric inner disc may contribute to
the observed X-ray and optical periodicities in the light curves of these
systems. In contrast to the stream-fed accretion model for these periodicit
ies, the tidal picture predicts that modulation can exist even for systems
with weaker magnetic fields where the magnetospheric radius is smaller than
the radius of periastron of the mass transfer stream. We also predict that
additional periodic components should exist in the emission from low-mass-
ratio intermediate polars displaying superhumps.