Applications of Regularized Smoothed Particle Hydrodynamics to gravitationally dominated fluids in astrophysics

Gravitation plays a dominant role in the evolution of many astrophysical systems ranging in length scales from the large-scale structuring of the universe, to the formation and interaction of galaxies, stars, and individual proto-planetary discs. With st eadily increasing resolution, observational data give us valuable insight into a wide variety of phenomena that characterize these systems. Even so, many of the underlying processes are inherently chaotic, and possibly turbulent. In addition, the time sca les of the problems are typically so large that they prevent us from observing other than mere snapshots of much longer evolutions. It is therefore important to compliment observations with data from numerical simulations. Considering the enormous computa tional challenges often faced when trying to simulate many astrophysical applications, it is of vital importance for gaining new insight into these applications to develop and improve relevant numerical methods. The purpose of this project is to apply the method Regularized Smoothed Particle Hydrodynamics (RSPH) to astrophysical applications such as planet and star formation and the evolution of large-scale structures in a cold dark matter dominated universe, where gravitation combined with thermal, and p ossibly magnetic forces play a dominant role in the evolution of these systems. RSPH has been developed as an extension to Smoothed Particle Hydrodynamics (SPH), a method which has been applied to studies of astrophysical fluids for almost 30 years. Howev er, tests of non-gravitational problems seem to indicate that RSPH can provide a better accuracy-to-cost ratio than conventional SPH. It is also our belief that RSPH has the potential of eliminating some of the fundamental problems of conventional SPH, wi thout loosing many of the desirable features of the latter method. In this way, we hope that RSPH will be a valuable addition to existing methods in studying gravitational (magneto-)hydrodynamics.