MERCREDI 18 FEVRIER 2009 14 heures Salle Séminaire 5 Centre de Physique Théorique Marseille-Luminy P. J. Morrison Department of Physics and Institute for Fusion Studies, University of Texas, Austin, USA Title: Building action principles for magnetofluid models Abstract: An algorithmic prescription is described for building action principles for plasma magnetofluid models that are extensions of magnetohydrodynamics. The action principles naturally lead to physically important invariants and Hamiltonian structure. Also, a prescription for obtaining reduced fluid models is given. Examples relevant to laboratory plasma discharges and naturally occurring plasmas will be presented, including models with gyroviscosity and generalizations of Ohm's law.