NONLINEAR INTERCHANGE MODE IN EDGE PLASMA WITH POLOIDAL SHEAR-FLOW

Nonlinear evolution of two dimensional pressure-driven interchange mod e produces relaxation oscillations in the presence of poloidal shear f low for Rayleigh number Ra similar to 10(4). Here the flow velocity ha s a symmetric profile with respect to the center of slab plasma where the velocity shear disappears. There is a tendency that the velocity s hear becomes weak after the saturation. When the velocity shear almost disappears, fluctuations grow rapidly. Then the velocity shear is aga in generated to suppress the growth of fluctuations. This kind of rela xation oscillation may be related to ELM [Edge Localized Mode] in the H-mode of tokamak.