Stormtime observations of the flux of plasmaspheric ions to the dayside 
cusp/magnetopause

J. C. Foster, A. J. Coster, P. J. Erickson, F. J. Rich, B. R. Sandel


For the large geomagnetic disturbance on April 11, 2001, we combine data from
the Millstone Hill radar, a network of GPS TEC receivers, and the DMSP F-12 and
IMAGE satellites, to estimate the sunward flux of thermal plasma associated with
erosion of the outer plasmasphere/ionosphere in the dusk sector. Direct radar
observations of the E X B advection of SED plasma determine a flux of >10E26
ions/s to the noontime cusp at F-region heights. DMSP in situ observations
provide a similar estimate. Assuming a dipolar magnetic field, we project our
low-altitude observations into the outer plasmasphere, obtaining a total sunward
flux of >10E27 ions/s. High-altitude IMAGE EUV observations of the plasmasphere
drainage plume provides an estimate of 1.5 X 10E27 ions/s for the sunward flux.
Such rates of sunward plasma transport are sufficient to deplete a 1-Re shell of
the outer plasmasphere in ~1 hour.

_______________
Geophysical Research Letters, 31, L08809, doi:10.1029/2004GL020082, 2004