Dynamic behavior of the L-H transition
Abstract
The dynamic behavior of the L-H transition in the ASDEX-Upgrade tokamak is described. We focus on the periodic L-H-L transitions known as ``dithering H mode'' and show that there is an intrinsic time scale in this process which is characteristic for the L-H transition. We give a tentative explanation for the phenomenon using an extension of Itoh's model for the L-H transition and find that this simple bifurcation model can qualitatively explain many of the experimental observations. According to our model, the dithering cycles are a limit cycle oscillation due to a difference in the response of the system to a rise in either T or n. The implications for H-mode theories are discussed.
- Publication:
-
Physical Review Letters
- Pub Date:
- January 1994
- DOI:
- 10.1103/PhysRevLett.72.222
- Bibcode:
- 1994PhRvL..72..222Z
- Keywords:
-
- 52.55.Fa;
- 52.55.Pi;
- Tokamaks spherical tokamaks;
- Fusion products effects fast particle effects