Linear study of ionic turbulence in tokamaks
For some time, the ion heat diffusivity has been found experimentally to be in good agreement with neoclassical values in tokamaks. In some cases the ion heat transport is anomalous. This confinement degradation is suspected to be caused by an ionic turbulence. Nevertheless threshold values given in the literature are achieved in many discharges without any enhancement of the ion transport. This paper re-assesses the theory and checks these threshold values. Two results are found. Firstly the most dangerous modes are large scale ballooned instabilities driven by trapped ions. Secondly, the critical thermal gradient length normalised to the major radius is smaller than previously predicted. Ion modes are therefore more stable.
Bibliographic Reference: Paper presented: International School of Plasma Physics-Theory of Plasma Physics, Varenna (IT), August 27-31, 1990
Availability: Available from (1) as Paper EN 35709 ORA
Record Number: 199011693 / Last updated on: 1994-12-02
Original language: en
Available languages: en