УДЕРЖАНИЕ ЗАРЯЖЕНННЫХ ЧАСТИЦ В ТОКАМАКЕ С МАГНИТНЫМИ ОСТРОВАМИ

CONFINEMENT OF CHARGED PARTICLES IN A TOKAMAK WITH MAGNETIC ISLANDS

The behavior of charged particles in a tokamak magnetic configuration with split magnetic surfaces in the form of islands is studied. Such configuration can be clearly described in terms of Hamiltonian function [1] using general representation of the magnetic field. The trajectories of the motion of passing and trapped particles in the magnetic configuration with islands are calculated. Particular attention is paid to the case when the width of the island in the radial (along the minor radius) direction is greater than the characteristic width of the "banana" orbit of trapped particle. It is shown that existence of magnetic island has no significant influence on the shape of banana orbit: trapped particle in its motion can cross the separatrix between the magnetic island and nested magnetic surfaces. Passing particle has a similar behavior. Depending on the value of the pitch angle, the Poincare cross-section of the motion trajectories for passing particles may have the standard oval shape and the shape with island structure.