Simulation of Soliton at Magnetopause Boundary
This movie shows a simulation of the electric field of an electrostatic zonal flow (red curve) at the Earth's magnetopause boundary (black curve: plasma density profile).
Upstream of the boundary, a stationary electrostatic wave, called a zonal flow, is excited by drift wave turbulence. Downstream, the drift waves are not in resonance with the zonal flow, so the zonal flow does not grow there. At the boundary itself, the action of the drift wave turbulence rips the zonal flow apart, causing individual zonal flow periods to move independently. This explains the origin of the solitary zonal flow structures observed by Cluster in regions of strong drift wave turbulence at the Earth's magnetopause boundary.