  Type Ia supernovae (SNe Ia) play a critical role in astrophysics, yet their
origin remains mysterious. A crucial physical mechanism in any SN Ia model is
the initiation of the detonation front which ultimately unbinds the white dwarf
progenitor and leads to the SN Ia. We demonstrate, for the first time, how a
carbon detonation may arise in a realistic three-dimensional turbulent
electron-degenerate flow, in a new mechanism we refer to as turbulently-driven
detonation. Using both analytic estimates and three-dimensional numerical
simulations, we show that strong turbulence in the distributed burning regime
gives rise to intermittent turbulent dissipation which locally enhances the
nuclear burning rate by orders of magnitude above the mean. This turbulent
enhancement to the nuclear burning rate leads in turn to supersonic burning and
a detonation front. As a result, turbulence plays a key role in preconditioning
the carbon-oxygen fuel for a detonation. The turbulently-driven detonation
initiation mechanism leads to a wider range of conditions for the onset of
carbon detonation than previously thought possible, with important
ramifications for SNe Ia models.
