TAPIR Seminar

We performed numerical relativity-magneto hydrodynamical simulations of binary neutron star merger on the Japanese supercomputer K.  The grid resolution of 70 m is highest among the binary neutron star merger simulations done so far and we did an in-depth resolution study to figure out the amplification mechanism of magnetic fields during the binary neutron star merger.

We found the Kelvin-Helmholtz instability developed in the shear layer at the merger significantly amplifies the magnetic field. A hyper-massive neutron star formed after the merger is subject to the non-axisymmetric magneto-rotational instability. These two amplification mechanisms do not work with an insufficient resolution. The star collapses to a black hole and a formed accretion disk is strongly magnetized a priori.

We found a coherent toroidal magnetic field inside the disk and not a coherent poloidal field above the black hole even after 60 ms after the black hole formation.