Supernovae of Type Ia are used as standard candles for cosmological
observations despite the as yet incomplete understanding of their explosion
mechanism. In one model, these events are thought to result from subsonic
burning in the core of an accreting Carbon/Oxygen white dwarf that is
accelerated through flame wrinkling and flame instabilities. Many such white
dwarfs have significant magnetic fields. Here we derive the linear effects of
such magnetic fields on one flame instability, the well-known Landau-Darrieus
instability. When the magnetic field is strong enough that the flame is
everywhere sub-Alfvenic, the instability can be greatly suppressed.
Super-Alfvenic flames are much less affected by the field, with flames
propagating parallel to the field somewh at destabilized, and flames
propagating perpendicular to the field somewhat stabili zed. Trans-Alfvenic
parallel flames, however, like trans-Alfvenic parallel shocks, are seen to be
non-evolutionary; understanding the behavior of these flames will require
careful numerical simulation.Comment: 31 pp, 11 fig, submitted to Ap