Matter Mixing in Axisymmetric Supernova Explosion

Abstract

Growth of Rayleigh-Taylor (R-T) instabilities under the axisymmetric explosion are investigated by two-dimensional hydrodynamical calculations. The degree of the axisymmetric explosion and amplitude of the initial perturbation are varied parametrically to find the most favorable parameter for reproducing the observed line profile of heavy elements. It is found that spherical explosion can not produce $^{56}Ni$ travelling at high velocity ($\sim 3000$km/sec), the presence of which is affirmed by the observation, even if the amplitude of initial perturbation is as large as 30%. On the other hand, strong axisymmetric explosion model produce high velocity $^{56}Ni$ too much. Weak axisymmetric explosion are favored for the reproduction of the observed line profile. We believe this result shows upper limit of the degree of the axisymmetric explosion. This fact will be important for the simulation of the collapse-driven supernova including rotation, magnetic field, and axisymmetric neutrino radiation, which have a possibility to cause axisymmetric supernova explosion. In addition, the origin of such a large perturbation does not seem to be the structure of the progenitor but the dynamics of the core collapse explosion itself since small perturbation can not produce the high velocity element even if the axisymmetric explosion models are adopted.