HR: 0800h
AN: SM21A-0459    [Abstracts]
TI: Lower Limit Of Plasma Densities At The Beginning Of Plasmaspheric Flux Tube Refilling
AU: * Tu, J
EM: Jiannan_Tu@uml.edu
AF: Center for Atmospheric Research, University Of Massachusetts Lowell, 600 Suffolk Street, Lowell, MA 01851 United States
AU: Song, P
EM: Paul_Song@uml.edu
AF: Center for Atmospheric Research, University Of Massachusetts Lowell, 600 Suffolk Street, Lowell, MA 01851 United States
AU: Reinisch, B W
EM: Bodo_Reinisch@uml.edu
AF: Center for Atmospheric Research, University Of Massachusetts Lowell, 600 Suffolk Street, Lowell, MA 01851 United States
AB: In this study we estimate the lower limit of the ion densities at the beginning of the flux tube refilling in the plasmasphere. We first calculate the densities of ions passing through the newly closed flux tubes in the magnetotail, i.e., the densities of the ions within the loss cone. The newly closed flux tubes drift earthward to the inner magnetosphere, where they may start to corotate with the earth and are subjected to the plasma refilling from the underlying ionosphere. Because of adiabatic compression, a portion of the passing ions become trapped, resulting in the increased ion densities within the flux tube. It is shown that the equatorial densities at the beginning of the refilling can not be zero but are at least several to several hundreds cm$^{-3}$, depending on how close the flux tubes drift toward the earth and how large the ion density at the topside ionosphere is. The finite plasmaspheric flux tube densities are consistent with the measurements from the Radio Plasma Imager (RPI) on the IMAGE spacecraft, which suggest that the depleted flux tubes maintain equatorial densities of tens to hundreds cm$^{-3}$ at $L = 3.7-2.2$. This estimated lower limit of the densities has important implication to the early stage refilling of the plasmaspheric flux tubes.
DE: 2730 Magnetosphere--inner
DE: 2736 Magnetosphere/ionosphere interactions
DE: 2740 Magnetospheric configuration and dynamics
DE: 2768 Plasmasphere
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting