Energy-conserving finite-β electromagnetic drift-fluid equations (original) (raw)

Saint Michael's College Colchester, VT 05439, USA Nonlinear energy-conserving drift-fluid equations that are suitable to describe selfconsistent finite-β low-frequency electromagnetic (drift-Alfvén) turbulent fluctuations in a nonuniform, anisotropic, magnetized plasma are derived from a variational principle. The variational principle is based on a drift-fluid Lagrangian that contains linear and nonlinear E × B velocities derived directly from the corresponding singleparticle finite-β gyrocenter Hamiltonian (in the zero-Larmor-radius limit). Covariant electromagnetic effects introduce a magnetic generalization to the standard ion polarization density as well as introduce a new ion magnetization current, which are both missing from existing gyrofluid and drift-fluid Poisson-Ampère equations. An exact energy conservation law is also derived directly from the drift-fluid Lagrangian by application of the Noether method.