A consistent and numerically stable family of plasma fluid models

Plasma fluid models satisfy conservation laws, implying physical consistency, that are seldom exactly satisfied by numerical codes. We demonstrate how to derive fluid models that combine consistency and numerical stability with a simple and flexible implementation. We exploit the anti-symmetric form of the plasma flow operator, which becomes apparent when the equations are written using generalized moments related to conserved quantities [1]. The plasma velocity generates infinitesimal rotations of the fluid, implying time reversibility. The resulting models possess discrete analogs that inherit important properties of the analytic forms, including conservation laws and positivity preservation. An advantage of this approach is its simplicity and flexibility. We apply our methodology to the Braginskii model, the MHD equations, and also drift-ordered models. Conservation properties are verified using single seeded blob motion and the Orzsag-Tang vortex, obtaining high-fidelity simulation results with negligible dissipation. [1] F.D. Halpern and R.E. Waltz, Phys.Plasmas 25, 060703 (2018).