  We report a two-stage crash process in edge localized mode (ELM) driven by
resistive drift-ballooning modes (RDBMs) numerically simulated in a full
annular torus domain. In the early nonlinear phase, the first crash is
triggered by linearly unstable RDBMs and m/n = 2/1 magnetic islands are
nonlinearly excited via nonlinear couplings of RDBMs. Simultaneously, middle-n
RDBM turbulence develops but is poloidally localized around X-points of the
magnetic islands, leading to the small energy loss. Here m is the poloidal mode
number, n is the toroidal mode number, the q = 2 rational surface exists at the
pressure gradient peak, and q is the safety factor, respectively. The second
crash occurs in the late nonlinear phase. Low-n magnetic islands are also
excited around the q = 2 surface via nonlinear couplings among the middle-n
turbulence. Since the turbulence develops from the X-points of higher harmonics
of m/n = 2/1 magnetic islands, it expands out poloidally. The second crash is
triggered when the turbulence covers the whole poloidal region. A scan of
toroidal wedge number N, where full torus is divided into N segments in the
toroidal direction, also reveals that the first crash process becomes more
prominent with the higher toroidal wedge number where the RDBMs play a dominant
role. These results indicate that nonlinear interactions of all channels in the
full torus domain can significantly affect the trigger dynamics of ELMs driven
by the RDBMs.
