Characteristic Boundary Conditions for Numerical Magnetohydrodynamic (MHD) Simulation of Solar and Laboratory Plasma Flows

摘要

We discuss the self-consistent time-dependent numerical bound-ary conditions for magnetohydrodynamic (MHD) simulation to study the solar and laboratory plasma dynamics. It is well known that these plasma flows cover from the sub-sonic and sub-Alfvenic to super-sonic and super-Alfvenic region. Mathematically, the set of governing differential equations is transited from el-liptical to hyperbolic type. In order to assure self-consistency, characteristic boundary conditions need to be used because the information propagating ac-cording to these characteristics will affect the solutions inside the computational domain. To illustrate the importance of the characteristic boundary conditions, two examples are given; one for solar plasma which is to study the energy and magnetic flux from the sub-photosphere to the corona, and the other one con-cerns laboratory plasma flow for the investigation of sub-Alfvenic inlet boundary conditions of an MHD nozzle flow.