A new method of particle motion control in toroidal magnetic traps with a rotational transform using an estafette of drift resonances and stochasticity of particle trajectories is proposed. The use of the word estafette here means that particles pass through a set of resonances in consecutive order from one to another during their motion. The overlapping of adjacent resonances can be moved radially from the centre to the edge of the plasma by switching on the corresponding perturbations at times in accordance with a particular rule. In this way, particles (e.g., cold alpha particles) can be removed from the centre of the confinement volume to the plasma periphery. For an analytical treatment of the stochastic behaviour of particle motion, the equation for the drift surface function Ψ* (r,ϑ,φ,V∥,V⊥,t) = const is reduced to a diffusion type equation in the case when some adjacent resonances take place and the stochastic diffusion coefficients Dr,r, Dr,ϑ and Dϑ,ϑ in the real space variables are introduced. This new approach is demonstrated by numerical computations of test helium particle trajectories in the LHD toroidal trap.
Determination of broken KAM surfaces for particle orbits in toroidal confinement systems