Edge Localized Modes as New Bifurcation in Tokamaks

Sanae-I. Itoh; Kimitaka Itoh; Atsushi Fukuyama; Masatoshi Yagi

doi:10.1103/PhysRevLett.76.920

Edge Localized Modes as New Bifurcation in Tokamaks

Sanae-I. Itoh, Kimitaka Itoh, Atsushi Fukuyama, and Masatoshi Yagi

Phys. Rev. Lett. 76, 920 – Published 5 February 1996

Abstract

A model of giant edge localized modes in tokamaks is developed. The theory of self-sustained turbulence of a current-diffusive ballooning mode is extended. A bifurcation from the H mode to a third state with magnetic braiding, the M mode, is found to occur if the pressure gradient reaches a critical value. Nonlinear excitation of magnetic perturbation takes place, followed by catastrophic increase of transport. With backtransition to the $H (L)$ mode, a new hysteresis is found in the gradient-flux relation. The process then repeats itself. Avalanche of transport catastrophe across the plasma radius is analyzed.

Received 18 September 1995

DOI:https://doi.org/10.1103/PhysRevLett.76.920

Authors & Affiliations

Sanae-I. Itoh¹, Kimitaka Itoh², Atsushi Fukuyama³, and Masatoshi Yagi¹

¹Research Institute for Applied Mechanics, Kyushu University 87, Kasuga 816, Japan
²National Institute for Fusion Science, Nagoya 464-01, Japan
³School of Engineering, Okayama University, Okayama 700, Japan