Long-Lived Plasmaspheric Drainage Plumes and the Plasma-Source Dilemma

English Abstract:

Long-lived (weeks) plasmaspheric drainage plumes during long-lived high-speed-stream-driven storms were explored. Geosynchronous-orbit spacecraft see the plumes as streams of dense plasmaspheric plasma continuously advecting sunward toward the dayside magnetopause. The standard assumption is that the plasmaspheric plumes are the drainage of plasma from a built-up outer plasmasphere. Computer simulations indicate that drainage from the outer plasmasphere can only supply a plume for about 2 days. Plumes that are 5 days old are common and plumes lasting 15 days have been seen. The question arises for long-lived plumes (and for any plume older than about 2 days): Where is the plasma coming from? Magnetospheric sources and ionospheric sources will be explored.