Stochastic fluctuation and transport in the edge tokamak plasmas with the resonant magnetic perturbation field

The stochastic layer formation by the penetration of the resonant magnetic perturbation (RMP) field has been considered as a key mechanism in the RMP control of the edge localized mode (ELM) in tokamak plasmas. Difficulty in quantifying the stochasticity has limited the assessment of the stochastic field effect in the pedestal transport to ambiguous inference from the pressure profile change. Here, we suggest the rescaled complexity for an effective measure of the stochasticity in the fluctuation and transport. This could be used to identify the narrow and localized stochastic layer around the pedestal top and estimate its width. We found that the fluctuation and transport in the edge plasmas become more stochastic with the more penetration of the RMP field into the plasma, which supports the importance of the stochastic layer formation in the RMP ELM control experiment.