Pseudo-three-dimensional turbulence in magnetized nonuniform plasma

Abstract

A simple nonlinear equation is derived to describe the pseudo‐three‐dimensional dynamics of a nonuniform magnetized plasma with T_e≫T_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^1.8(1+k²)^−2.2, while the width of the frequency spectrum is proportional to k³(1+k²)⁻¹, where k is normalized by c_s/ω_ci. The result compares well with the recently observed spectrum in the ATC tokamak.