Pseudo-three-dimensional turbulence in magnetized nonuniform plasma

A simple nonlinear equation is derived to describe the pseudo-three-dimensional dynamics of a nonuniform magnetized plasma with T/sub e/>>T/sub i/ by taking into account the three-dimensional electron, but two-dimensional ion dynamics in the direction perpendicular to B0. The equation bears a close resemblance to the two-dimensional Navier--Stokes equation. A stationary spectrum in the frequency range of drift waves is obtained using this equation by assuming a coexisting large amplitude long wavelength mode. The ω-integrated k spectrum is given by k/sup 1.8/(1+k2)/sup -2.2/, while the width of the frequency spectrum is proportional to k3(1+k2)-1, where k is normalized by c/sub s//ω/sub c i/. The result compares well with the recently observed spectrum in the ATC tokamak