The multidimensional structure of detonations in type Ia supernovae

Many current models of Type Ia supernovae involve detonations at some phase of the explosion. Experimental and computational results for detonations in terrestrial fuel-air mixtures show that multidimensional effects are critical to understanding the initiation, propagation, and quenching of real detonations. Multidimensional calculations produce structures that can lead to unsteady detonation propagation in simulations of fuel-air mixtures, in agreement with experiments. We present here the first results to demonstrate the presence of multidimensional effects in detonations in degenerate carbon-oxygen matter. Our simulations show that perturbations induce transverse waves in the carbon-burning layer that interact and create pockets of incompletely burned material. This increases the effective size of the burning region, reduces the detonation velocity, and produces a different composition distribution in the detonated material relative to those predicted by one-dimensional calculations.