Partager cette page :

Variational averaging of charged-particle motion in strong magnetic fields

le 3 avril 2019

11h - Groupe de travail "Applications des Mathématiques"

ENS Rennes salle 7

Séminaire de Stefan Possaner (Munich) au groupe de travail "Applications des mathématiques"

Groupe de travail


Lien vers la page Web de l'orateur

Résumé :
Symmetries play an important role in the equations of plasma physics. Theses symmetries are manifest in various conservation laws, like volume preservation of the flow of a charged particle, or energy conservation, for instance. Numerical codes that mimic such symmetries often show increased stability and accuracy. We present a theory called “variational averaging” which provides an averaging procedure of the fast time scale (cyclotron frequency) on the level of the variational principle of the dynamics, thereby guaranteeing the preservation of symmetries. Our approach is related to the theory of "gyrokinetics", but does not require the use of Lie transforms or Lie derivatives. We discuss the scaling procedure that leads to the non-dimensional particle-field Lagrangian and then discuss the asymptotic limit of the variational principle as the magnetic field strength tends to infinity.

Recherche - Valorisation
Nicolas Crouseilles, Thibaut Deheuvels et Frédéric Marbach

Mise à jour le 27 mars 2019