B. C. Stephens

Magnetorotational collapse of massive stellar cores to neutron stars : Simulations in full general relativity

We study magnetohydrodynamic (MHD) effects arising in the collapse of magnetized, rotating, massive stellar cores to proto-neutron stars (PNSs). We perform axisymmetric numerical simulations in full general relativity with a hybrid equation of state. The formation and early evolution of a PNS are followed with a grid of

Relativistic magnetohydrodynamics in dynamical spacetimes: Numerical methods and tests

2500\ifmmode\times\else\texttimes\fi{}2500

Evolution of magnetized, differentially rotating neutron stars: Simulations in full general relativity

zones, which provides better resolution than in previous (Newtonian) studies. We confirm that significant differential rotation results even when the rotation of the progenitor is initially uniform. Consequently, the magnetic field is amplified both by magnetic winding and the magnetorotational instability (MRI). Even if the magnetic energy

Collapse of magnetized hypermassive neutron stars in general relativity.

{E}_{\mathrm{EM}}

Eccentric black hole-neutron star mergers: effects of black hole spin and equation of state

is much smaller than the rotational kinetic energy

ECCENTRIC BLACK-HOLE-NEUTRON-STAR MERGERS

{T}_{\mathrm{rot}}

Hydrodynamics in full general relativity with conservative adaptive mesh refinement

at the time of PNS formation, the ratio

Excitation of magnetohydrodynamic modes with gravitational waves: A testbed for numerical codes

{E}_{\mathrm{EM}}/{T}_{\mathrm{rot}}

Collapse of magnetized hypermassive neutron stars in general relativity: Disk evolution and outflows

increases to 0.1\char21{}0.2 by the magnetic winding. Following PNS formation, MHD outflows lead to losses of rest mass, energy, and angular momentum from the system. The earliest outflow is produced primarily by the increasing magnetic stress caused by magnetic winding. The MRI amplifies the poloidal field and increases the magnetic stress, causing further angular momentum transport and helping to drive the outflow. After the magnetic field saturates, a nearly stationary, collimated magnetic field forms near the rotation axis and a Blandford-Payne\char21{}type outflow develops along the field lines. These outflows remove angular momentum from the PNS at a rate given by

Collapse and black hole formation in magnetized, differentially rotating neutron stars

\stackrel{\ifmmode \dot{}\else \textperiodcentered \fi{}}{J}\ensuremath{\sim}\ensuremath{\eta}{E}_{\mathrm{EM}}{C}_{B}