A Very Fast And Angular Momentum Conserving Tree Code
arXiv:1706.06989 · doi:10.3847/1538-3881/aa7b2f
Abstract
There are many methods used to compute the classical gravitational field in astrophysical simulation codes. With the exception of the typically impractical method of direct computation, none ensure conservation of angular momentum to machine precision. Under uniform time-stepping, the Cartesian fast multipole method of Dehnen (also known as the very fast tree code) conserves linear momentum to machine precision. We show it is possible to modify this method in a way that conserves both angular and linear momenta.
13 pages, 1 figure, accepted for publication by AAS Journals, unnecessary boldface removed