Nonlinear Self-Sustained Drift-Wave Turbulence

Abstract

Numerical simulations of 3D collisional drift-wave turbulence in a sheared magnetic field are presented which demonstrate that fluctuations are self-sustaining even though the linear eigenmodes of the system are all damped. An analytic calculation reveals that the source of the turbulence is a nonlinear streaming instability in which radial flows extract energy from the ambient density gradient and drive drift waves which then amplify the radial flow.