ABSTRACT:
Many physical contexts involve the interplay of different phenomena at different scales. The corresponding description requires the use of multi-physics models, whose mathematical formulation poses several challenges. Examples are found in the classical-quantum coupling in molecular dynamics or in the coupling between mean flow and fluctuation kinetics in turbulence. In plasma physics, the interaction of energetic particles (obeying kinetic theory) with a fluid bulk (obeying magnetohydrodynamics) requires formulating hybrid kinetic-fluid models, which are the subject of this talk. These models are often obtained by making assumptions on the equations of motion, although this operation may destroy fundamental properties such as energy balance. The use of symmetry techniques in mechanical systems is shown to provide a unifying framework for coupling nonlinear kinetic and fluid theories in a consistent way, thereby leading to new hybrid plasma models. Then, a comparison study is presented in terms of linear and nonlinear stability.
ADDITIONAL INFORMATION:
Cesare’s research interests include Hamiltonian/Lagrangian systems on Lie groups and inviscid fluid flows; Lie symmetry methods for collisionless kinetic equations and their moments; Geometry of multiphysics models in hybrid kinetic-fluid and classical-quantum dynamics. http://www2.surrey.ac.uk/maths/people/cesare_tronci/