National Institute for Fusion Science, Nagoya 464-01, Japan
(Received September 11, 1991; Accepted November 1, 1991)
Keywords: Magnetic Field Line, Magnetic Chaos, Tearing Mode, Magnetic Island
Abstract. The magnetic structure of the toroidal configuration is composed of regions either with the regular magnetic surface or with the chaotic field line. Increase of unstable magnetic perturtations grows a chaotic region, which often activates time evolution of plasma. In the nonlinear process of resistive tearing instability, the disappearance of a magnetic island in the chaotic magnetic region is followed by the rapid formation of a bubble structure of the current density.