Return To: Session TH1 - Theory 1 (Tuesday, 20 October)
Prev Page: (TH1/5) Self-Consistent Computation of Transport Barrier Formation by
Next Page: (TH1/D) Discussion of Session TH1

(TH1/6) Formation and Collapse of Internal Transport Barrier

   
A. Fukuyama 
Department of Nuclear Engineering, Kyoto University, Kyoto, Japan
 
K. Itoh 
National Institute for Fusion Science, Toki, Gifu, Japan
 
S.-I. Itoh , M. Yagi 
Research Institute for Applied Mechanics, Kyushu University, Kasuga, Fukuoka, Japan

Abstract
A theoretical model of internal transport barrier (ITB) is developed. The transport model based on the self-sustained turbulence theory of the current-diffusive ballooning mode is extended to include the effects of $E\times B$ rotation shear. Delayed formation of ITB is observed in transport simulations. The influence of finite gyroradius is also discussed. Simulation of the current ramp-up experiment successfully described the radial profile of density, temperature and safety factor. A model of ITB collapse due to magnetic braiding is proposed. Sudden enhancement of transport triggered by overlaping of magnetic islands terminates ITB. The possibility of destabilizing global low-$n$ modes is also discussed.

     

Read the full paper in PDF format.