Novel effects of stochastic noise on the Low-to-High Confinement transitions and edge localized modes

While the low-to-High mode (L-H) transition and Edge localized modes have been described from a deterministic view point, their dynamics can fundamentally be affected by stochastic noises. In this talk, I will report such novel effects of stochastic noises on the dynamics of the L-H transition and ELMs by using a non-perturbative statistical theory. First, I will show how a stochastic noise can facilitate the transitions to the self-regulatory oscillatory (dithering) phase and the H-mode as well as leading to a mixed dithering-H-mode state. Furthermore, it will be shown that a probability density function (PDF) changes in time over the L-H transition and can be strongly non-Gaussian; intermittent zonal flows can appear and play an important role in regulating turbulence in the transitions. Second, I will discuss the effects of stochastic particle and magnetic perturbations on ELM suppression and mitigation via phase mixing. Furthermore, it will be shown that stochastic noises can significantly reduce power and energy losses caused by ELMs and reproduce the observed experimental scaling relation of the ELM power loss with the input power.