Loss ion orbits at the tokamak edge
Experiments have shown that additional heating can establish high ion temperatures just inside the last closed flux surface (LCFS), thus reducing the local ion collisionality. This may lead to collisionless escape of ions from this layer directly through the X-point to the divertor target plates. Such ion losses have two major consequences: (i) ions with energies of the order of 1 keV increase sputtering of the material of the target tiles; (ii) ion losses change the electric potential inside the LCFS. In this paper a systematic analysis of the effect of a radial electric field on fast-ion losses is performed. Both negative and positive potentials inside the LCFS are considered, with emphasis on the profile effects in the potential distribution.
Bibliographic Reference: Report: JET-P(93)25 EN (1993) 21 pp.
Availability: Available from the Publications Officer, JET Joint Undertaking, Abingdon, Oxon. OX14 3EA (GB)
Record Number: 199310976 / Last updated on: 1994-11-29
Original language: en
Available languages: en