Non-conservation of momentum in the FMM method in the PHANTOM code

M. Sh. Potashov


Abstract: The article discusses the implementation of the fast multipole method (FMM) in the PHANTOM code. It has been demonstrated that for any given pair of mutual interaction cells in a kd-tree, Newton's third law holds. However, momentum is not preserved for the entire system as a whole.

Keywords: smoothed particle hydrodynamics, SPH, tree code, fast multipole method, FMM, PHANTOM, N-body.

DOI: 10.20948/prepr-2024-43