TY - JOUR
T1 - High-resolution simulations of convection preceding ignition in Type 1a supernovae using adaptive mesh refinement
AU - Nonaka, A.
AU - Aspden, Andrew
AU - Zingale, M.
AU - Almgren, A.
AU - Bell, J.
AU - Woosley, S.
PY - 2012/1/20
Y1 - 2012/1/20
N2 - We extend our previous three-dimensional, full-star simulations of the final hours of convection preceding ignition in Type Ia supernovae to higher resolution using the adaptive mesh refinement capability of our low Mach number code, MAESTRO. We report the statistics of the ignition of the first flame at an effective 4.34 km resolution and general flow field properties at an effective 2.17 km resolution. We find that off-center ignition is likely, with radius of 50 km most favored and a likely range of 40-75 km. This is consistent with our previous coarser (8.68 km resolution) simulations, implying that we have achieved sufficient resolution in our determination of likely ignition radii. The dynamics of the last few hot spots preceding ignition suggest that a multiple ignition scenario is not likely. With improved resolution, we can more clearly see the general flow pattern in the convective region, characterized by a strong outward plume with a lower speed recirculation. We show that the convective core is turbulent with a Kolmogorov spectrum and has a lower turbulent intensity and larger integral length scale than previously thought (on the order of 16 km s–1 and 200 km, respectively), and we discuss the potential consequences for the first flames.
AB - We extend our previous three-dimensional, full-star simulations of the final hours of convection preceding ignition in Type Ia supernovae to higher resolution using the adaptive mesh refinement capability of our low Mach number code, MAESTRO. We report the statistics of the ignition of the first flame at an effective 4.34 km resolution and general flow field properties at an effective 2.17 km resolution. We find that off-center ignition is likely, with radius of 50 km most favored and a likely range of 40-75 km. This is consistent with our previous coarser (8.68 km resolution) simulations, implying that we have achieved sufficient resolution in our determination of likely ignition radii. The dynamics of the last few hot spots preceding ignition suggest that a multiple ignition scenario is not likely. With improved resolution, we can more clearly see the general flow pattern in the convective region, characterized by a strong outward plume with a lower speed recirculation. We show that the convective core is turbulent with a Kolmogorov spectrum and has a lower turbulent intensity and larger integral length scale than previously thought (on the order of 16 km s–1 and 200 km, respectively), and we discuss the potential consequences for the first flames.
U2 - 10.1088/0004-637X/745/1/73
DO - 10.1088/0004-637X/745/1/73
M3 - Article
SN - 0004-637X
VL - 745
SP - 73
JO - The Astrophysical Journal
JF - The Astrophysical Journal
IS - 1
ER -