Collisionless fast ions dynamics in Tokamaks
In thermonuclear plasmas of the next Tokamak generation, the dynamics of fusion products needs to be understood as it could well influence reactor performances. In such a low collisionnality regime, a careful analysis of the associated transport and relaxation processes is required. For this program to be completed, the effect of a perturbing field on fast particle individual motion must be precisely evaluated. This imposes a requirement to address the question within Hamiltonian mechanics. In this framework, resonances of particle trajectories with low frequency fields arise naturally as a potential mechanism for transport and relaxations. The latter processes result from the destruction of adiabatic invariants when a stochasticity threshold is reached. Then, the quasi-linear theory is applicable, and diffusion coefficients can be derived. In this paper, the method is briefly reviewed and two reactor relevant situations analysed: heating of energetic ions under the effect of a compressionnal wave, and alpha-particle losses induced by the toroidal field ripple.
Bibliographic Reference: Paper presented: 16th European Conference on Controlled Fusion and Plasma Physics, Venezia (IT), March 13-17, 1989
Availability: Available from (1) as Paper EN 34460 ORA
Record Number: 198910805 / Last updated on: 1994-12-01
Original language: en
Available languages: en