Heavy ion circulation in the Earth's magnetosphere

We propose a mechanism whereby singly charged heavy ions from the plasmasphere are convected intermittently to the dayside magnetopause, accelerated there, swept into the distant tail lobes and boundary layer and convected earthward in the plasma sheet to re‐enter the inner magnetosphere. The outer region of the plasmasphere is known to be stripped off during periods of enhancement of the convection electric field. These cold plasmaspheric ions drift toward the dayside magnetopause where they may become accelerated and co‐mingled with magnetosheath plasma either through magnetic merging or some viscous process operating at the magnetopause. If the ion motion at the magnetopause is poleward, the ions may become part of the entry layer, entering the cusp and exiting as part of the plasma mantle. The cross‐tail electric field will cause them to drift into the lobes toward the center of the tail, ultimately reaching the plasma sheet in the distant tail. If the ion motion at the dayside magnetopause is equatorial, the plasmaspheric ions become part of the boundary layer, again ultimately reaching the plasma sheet in the distant tail. Once in the plasma sheet some of the heavy ions may flow back toward the earth and re‐enter the magnetosphere as energetic ions.