Hamiltonian study of the response of a tokamak plasma to the ion cyclotron heating wave : Minority heating and fast wave current drive
The role of additional heating, such as ion cyclotron heating, is to raise magnetic fusion plasmas to higher temperatures, to satisfy the ignition condition. The understanding of the wave absorption mechanism requires a precise description of the particle individual trajectories. Hamiltonian mechanics can do this using action-angle variables. A quantitative evaluation of the intrinsic stochasticity for ionic trajectories perturbed by the fast wave is derived. This stochasticity, combined with the collisional effects, gives the validity domain for a quasilinear approximation of the evaluation equation. This equation is then written under a variational formulation, and solved semi-analytically. Results point to the importance of Hamiltonian chaos in the formation of the deeply anisotropic distribution tails, encountered in minority heating scenarios. Direct interaction of the electrons and the fast wave is similarly analysed. The influence of the various parameters (wave spectrum, magnetic configuration, frequency) is then examined in order to optimise this scenario of fast wave current drive in tokamaks.
Bibliographic Reference: Report: EUR-CEA-FC-1400 FR (1990)
Availability: Available from CEA, Département de Recherches sur la Fusion Contrôlée, Saint-Paul-lez-Durance (FR)
Record Number: 199011302 / Last updated on: 1994-12-01
Original language: fr
Available languages: fr