SphericalNR: GRMHD Simulations in Curvilinear Coordinates

Many strongly gravitating astrophysical GRMHD systems exhibit approximately cylindrical symmetry in the bulk motion of the fluid. In this talk, we describe a new code, SphericalNR, that is used to evolve such    systems in curvilinear coordinates. Basing the numerical algorithms on curvilinear coordinates can provide higher accuracies, with smaller computational grids, when compared to Cartesian coordinates. In this talk, we present the challenges and successes in accurately evolving strongly gravitating systems such as unstable neutron stars and circumbinary accretion disks.