Fokker-Planck study of fast ion losses in JET
A recent study of direct losses of fast ions near the JET separatrix using a particle following code to trace the drift orbits has shown that the radial electric field can greatly modify the loss cone in velocity space. These calculations also suggest that a small negative potential within the plasma might lead to greater losses than with E(r) = 0. The 3D Fokker-Planck code BANDIT-3D has been modified to include the loss cones. The calculation of the ion distributions has been made on several, unconnected, circular flux surfaces clustered close to the separatrix with each flux surface having its own loss cone. The loss cones are calculated from the conserved quantities assuming a parabolic potential profile. This calculation is described and the qualitative features of the loss cones are explained, the Fokker-Planck equation is outlined, the results obtained are examined and conclusions are given.
Bibliographic Reference: Report: AEA FUS 253 EN (1993)
Availability: Available from the Librarian, UKAEA, Culham Laboratory, Abingdon, Oxon. OX14 3DB (GB)
Record Number: 199311644 / Last updated on: 1994-11-28
Original language: en
Available languages: en