The effect of sheared diamagnetic flow on turbulent structures generated by the Charney–Hasegawa–Mima equation

Abstract

The generation of electrostatic drift wave turbulence is modeled by the Charney–Hasegawa–Mima equation. The equilibrium density gradient n0=n0(x) is chosen so that dn0/dx is nonzero and spatially variable (i.e., v*e is sheared). It is shown that this sheared diamagnetic flow leads to localized turbulence which is concentrated at max(∇n0), with a large dv*e/dx inhibiting the spread of the turbulence in the x direction. Coherent structures form which propagate with the local v*e in the y direction. Movement in the x direction is accompanied by a change in their amplitudes. When the numerical code is initialized with a single wave, the plasma behavior is dominated by the initial mode and its harmonics.