Beltrami States for Plasma Dynamics Models

The various plasma models - incompressible magnetohydrodynamic (MHD) model, compressible MHD model, incompressible Hall MHD model, compressible Hall MHD model, electron MHD model, compressible Hall MHD with electron inertia model - notwithstanding the diversity of the underlying physics, are shown to exhibit some common features in the Beltrami states like certain robustness with respect to the plasma compressibility effects (albeit in the barotropy assumption) and the {\it Bernoulli} condition. The Beltrami states for these models are deduced by minimizing the appropriate total energy while keeping the appropriate total helicity constant. A Hamiltonian formulation framework is used to carry out these variational problems.