Minimal dynamic model for electron-temperature-gradient turbulence

The dynamical system for the toroidal electron-temperature-gradient (ETG) driven turbulence is investigated. Employing the low-order-truncation approximation, a set of coupling equations is derived to describe the minimal dynamic model for the ETG turbulence. Numerical simulation results show that there exist complex dynamical bifurcation behaviors in that turbulence. The onset of an electric local mode brings about the low to high (H) mode transition or the H to the barrier-localized/edge-localized mode (BLM/ELM) transition for the confinement in a tokamak. An interesting result is the onset of a magnetic local mode in the ETG turbulence system. It leads to the H to the magnetic high mode transition or the BLM/ELM to the magnetic BLM/ELM transition. (c) 2007 American Institute of Physics.