Three-dimensional particle simulation of drift-wave fluctuations in a sheared magnetic field

Three-dimensional particle simulations of collisionless drift waves in sheared magnetic fields were performed in order to determine the nonlinear behavior of inverse--electron-resonance dynamics in the presence of thermal fluctuations. It is found that stochastic electron diffuision in the electron-resonance overlap region can destabilize the drift-wave eigenmodes. Numerical evaluations based on a nonlinear electron-resonance broadening theory give predictions in accord with the frequency and growth rates found in the simulation of short-wavelength modes (k/sub y/rho/sub s/approx. >1)