  The delayed detonation model describes the observational properties of the
majority of type Ia supernovae very well. Using numerical data from a
three-dimensional deflagration model for type Ia supernovae, the intermittency
of the turbulent velocity field and its implications on the probability of a
deflagration-to-detonation (DDT) transition are investigated. From structure
functions of the turbulent velocity fluctuations, we determine intermittency
parameters based on the log-normal and the log-Poisson models. On the other
hand, the analysis of the turbulent velocity fluctuations in the vicinity of
the flame front by Roepke suggests a much higher probability of large velocity
fluctuations on the grid scale in comparison to the log-normal intermittency
model. Following Pan et al., we computed probability density functions for a
DDT for the different distributions. Assuming that a DDT can occur in the
stirred flame regime, as proposed by Woosley et al., the log-normal model would
imply a delayed detonation between 0.7 and 0.8 seconds after the beginning of
the deflagration phase for the multi-spot ignition scenario used in the
simulation. However, the probability drops to virtually zero if a DDT is
further constrained by the requirement that the turbulent velocity fluctuations
reach about 500 km/s. Under this condition, delayed detonations are only
possible if the distribution of the velocity fluctuations is not log-normal.
  From our calculations follows that the distribution obtained by Roepke allow
for multiple DDTs around 0.8 seconds after ignition at a transition density
close to 1x10^7 g/cm^3.
