Variational mean-fluctuation splitting and drift-fluid models

Abstract

After reviewing the variational approach to splitting mean flow and fluctuation kinetics in the standard Vlasov theory, the same method is applied to the drift-kinetic equation from Littlejohn's theory of guiding-center motion. This process sheds a new light on drift-ordered fluid (drift-fluid) models, whose anisotropic pressure tensor is then considered in detail. In addition, current drift-fluid models are completed by the insertion of magnetization terms ensuring momentum conservation. Magnetization currents are also shown to lead to challenging aspects when drift-fluid models are coupled to Maxwell's equations for the evolution of the electromagnetic field. In order to overcome these difficulties, a simplified guiding-center theory is proposed along with its possible applications to hybrid kinetic-fluid models.

Second version. Section 3.3 is new. Comments still welcome!

References in corpus (8)

• Hamiltonian approach to hybrid plasma models
• Variational approach to low-frequency kinetic-MHD in the current coupling scheme
• The Hamiltonian structure and Euler-Poincaré formulation of the Vlasov-Maxwell and gyrokinetic systems
• Neutral Vlasov kinetic theory of magnetized plasmas
• Nonlinear finite-Larmor-radius effects in reduced fluid models
• Application of the phase space action principle to finite-size particle plasma simulations in the drift-kinetic approximation
• A Lagrangian kinetic model for collisionless magnetic reconnection
• Charge-conserving, variational particle-in-cell method for the drift-kinetic Vlasov-Maxwell system