A Hybrid Acceleration for Self-gravity Calculation in Infinitesimally Thin Disks with Adaptive Mesh Refinement

Y.-H. Tseng et al. developed a direct approach for the computation of self-gravitational force to second-order accuracy based on adaptive mesh refinement. This direct approach is free of artificial boundary conditions, enabling realistic simulations of astronomical gaseous disks with speedups by graphics processing units (GPUs). On the other hand, the fast Fourier transform (FFT) on uniform grids requires variation in the number of zones. A hybrid method (HM) of the direct and the FFT methods can effectively replace the GPU acceleration in speeding up the computation. Numerical simulations demonstrate the computational time of the HM is less than that of the direct plus GPU acceleration and scales nearly linearly as the total number of zones when a sufficiently large number of zone sizes is selected. An application to a two-arm spiral is demonstrated for the generality of the proposed method.