TEST PARTICLE TRANSPORT DUE TO FLUCTUATING MAGNETIC FIELDS IN TOKAMAKS
The transport of charged test particles in the presence of given magnetic fluctuations and collisions is investigated from two approaches, namely, the Langevin and corresponding Fokker-Planck equations. Analytic discussion of the Fokker-Planck equation shows the radial particle and energy fluxes to be purely diffusive. The Langevin approach confirms the validity of the Fokker-Planck perturbative calculation for sufficiently small fluctuation amplitudes. From the Fokker-Planck theory we derive an effective parallel thermal diffusivity valid for all collisionalities, and show that the high collisionality result of Braginskii and the low collisionality form previously conjectured by the authors, are recovered. Application of the theory to TFR leads to qualitative agreement with the published observations.
Bibliographic Reference: WRITE TO THE LIBRARIAN, UKAEA, CULHAM LABORATORY, ABINGDON, OXON OX14 3DB (UK), MENTIONING REPORT CLM-P748, 1985
Record Number: 1989124055800 / Last updated on: 1987-01-01
Available languages: en