Numerical modelling of the neutral hydrogen dynamics for astrophysical problems

Abstract

Chemistry plays an important role in many astrophysical processes such as gravitational collapse, the evolution of disks, stars formation. The most of chemical processes for astrophysical problems are presented in classical notation for reactions. In order to simplify the usage of different kinetic schemes in large numerical simulation for solving astrophysical problems, we present the modification of CHEMPAK chemistry package developed by authors early. This modification consisting of the database for storing and editing kinetic, schemes, visual chemistry editor, pre-processor for translation target kinetic scheme to the system of ordinary differential equations (ODE) and a lot of open source ODE solvers such as RADAU5, DLSODES. The pre-processor can translate target kinetic scheme to the ODE system in Fortran or C++ notation for easy usage with a wide selection of mesh or mesh-less hydrodynamic codes. We present the kinetics study of molecular hydrogen formation process, and coupling the AstroPhi mesh hydrodynamic code, as an example of the new CHEMPAK modification usage.