TURBULENT DESTABILIZATION AND SATURATION OF THE UNIVERSAL DRIFT MODE IN A SHEARED MAGNETIC-FIELD

In a sheared magnetic field, turbulent diffusion of electrons in the vicinity of a mode rational surface can eliminate the stabilizing influence of nonresonant electrons and lead to an absolute instability at small but nonzero wave amplitudes. As the turbulence grows, the inverse electron Landau resonance is broadened in both velocity and configuration space, and the convective shear damping due to ions is enhanced by turbulent spatial broadening of the mode until saturation occurs. © 1979 The American Physical Society.