A TOPOLOGICAL APPROACH TO THE PROBLEM OF CHARGED-PARTICLE TRAJECTORIES IN A TOROIDAL AXISYMMETRICAL CONFIGURATION

This paper proposes a new approach for solving the general problem of Charged Particle Orbits in an axisymmetric toroidal configuration. This method is based upon the guiding center theory and gives a general and ''a priori'' classification of the topological properties of the trajectories. For a typical tokamak plasma, fifteen topological classes of orbits and their boundaries in a Constant-Of-Motion-space are found without any trajectory computation. The confinement of these energetic orbits into the plasma region is then discussed. The method remains useful for any arbitrary toroidal axisymmetric configuration, as X-points, doublets, etc., being strictly independent of the equilibrium mathematical form. This new approach may be applied mainly to charged fusion products and runaway electrons produced during disruptions. (C) 1995 American Institute of Physics.