- Tynan, GR;
- Xu, M;
- Diamond, PH;
- Boedo, JA;
- Cziegler, I;
- Fedorczak, N;
- Manz, P;
- Miki, K;
- Thakur, S;
- Schmitz, L;
- Zeng, L;
- Doyle, EJ;
- McKee, GM;
- Yan, Z;
- Xu, GS;
- Wan, BN;
- Wang, HQ;
- Guo, HY;
- Dong, J;
- Zhao, K;
- Cheng, J;
- Hong, WY;
- Yan, LW
Experiments on HL-2A, DIII-D and EAST show that turbulence just inside the last closed flux surface acts to reinforce existing sheared E × B flows in this region. This flow drive gets stronger as heating power is increased in L-mode, and leads to the development of a strong oscillating shear flow which can transition into the H-mode regime when the rate of energy transfer from the turbulence to the shear flow exceeds a threshold. These effects become compressed in time during an L-H transition, but the key role of turbulent flow drive during the transition is still observed. The results compare favourably with a reduced predator-prey type model. © 2013 IAEA, Vienna.