Multifractality in edge localized modes in Japan Atomic Energy Research Institute Tokamak-60 Upgrade

The temporal losses of confinement during edge localized modes in the Japan Atomic Energy Research Institute Tokamak-60 Upgrade (JT-60U) show multifra ctal scaling and the spectra are generally smooth, but in some cases there are signs of discontinuous derivatives. Dynamics of the Sugama-Horton model , interpreted as edge localized modes, also display multifractal scaling. T he spectra display singularities in the derivative, which can be interprete d as a phase transition. It is argued that the multifractal spectra of edge localized modes can be used to discriminate between different experimental discharges and validate edge localized mode models. (C) 2001 American Inst itute of Physics.