| This thesis presents an extended multi-fluid magnetohydrodynamic (MHD) models for fully- and partially-ionized anisotropic plasmas. New multi-fluid models for partially-ionized plasmas are developed based on the Gaussian moment closure for the Boltzmann equation of kinetic theory. The model, being coupled with Maxwell's equations, takes account of the multi-fluid properties and anisotropic nature of magnetized plasmas as well as reactive collisions such as ionization-recombination and charge-exchange collisions, which are missing from the conventional MHD model. The properties of the models are investigated numerically for one-dimensional problems by using a Godunov-type finite-volume scheme. The two-fluid model correctly recovers the MHD limit in the Brio-Wu-type shock tube problem. The three-fluid model recovers both the gas-dynamic and two-fluid limit, and also shows the capability of modelling partially ionized plasmas with reactive collisions such as ionization and recombination. |
