  Following unstable ignition of carbon, but prior to explosion, a white dwarf
(WD) in a Type Ia supernova (SN Ia) undergoes a simmering phase. During this
time, a central convective region grows and encompasses ~1 Msun of the WD over
a timescale of ~1000 yrs, which sets the thermal and turbulent profile for the
subsequent explosion. We study this time-dependent convection and summarize
some of the key features that differ from the traditional, steady-state case.
We show that the long conductive timescale above the convective zone and the
extraction of energy to heat the WD core leads to a decrease of the convective
luminosity and characteristic velocities near the convective zone's top
boundary. In addition, differences in the composition between the convective
core and the conductive exterior will significantly alter the location of this
boundary. In this respect, we find the biggest effect due to complete 22Ne
sedimentation prior to carbon ignition. These effects add diversity to the
possible WD models, which may alter the properties of the SN Ia explosion.
