TRANSIENT FLUX TUBES IN THE TERRESTRIAL MAGNETOSPHERE

We postulate that small, isolated density depletions are introduced into the magnetotail by an uneven plasma loading process in the far tail. Such bubbles would be displaced earthward by an interchange process, and a significant depletion would move faster than either the gradient‐curvature drift speed or the average convection speed. The dissolution of a bubble into the background results in a local reduction in plasma density, thereby violating ideal MHD and the subsequent conservation of plasma content. If a sufficient amount of magnetic flux in the far tail is contained in bubbles, then the net effect may be a reduction of plasma pressure in the near tail sufficient to resolve the pressure balance inconsistency. Copyright 1990 by the American Geophysical Union.