HR: 10:35h
AN: SM42A-02 [Abstracts]
TI: The Response of Dayside Ionospheric Upflows to Solar Wind Forcings
AU: * Wilson, G R
EM: gordon.wilson.ctr@hanscom.af.mil
AF: Boston College, 402 St. Clement's Hall
140 Commonwealth Ave, Chestnut Hill, MA 02467, United States
AU: Germany, G A
EM: germanyg@email.uah.edu
AF: Center for Space Plasma and Aeronomy Research, S131 Technology Hall
University of Alabama in Huntsville, Huntsville, AL 35899, United States
AB:
The ionosphere is clearly a significant source of magnetospheric plasma [Chappell et al., 1987] since terrestrial
ions have been discovered in the ring current [Johnson et al., 1977], the plasma sheet [Peterson et al., 1981], and
the tail lobes [Eastman et al., 1984]. The escape of plasma from the ionosphere to the magnetosphere is a
multi-step process that begins with upwelling of ionospheric plasma in the topside. Some distance above the
topside, the heavier ions (O+, N+, N2+, O2+, NO+) gain escape energy by one or more of a
multitude of wave-particle energization processes. Ionospheric upwelling does not always lead to plasma
escape since it can be part of the normal "breathing" of the atmosphere as it responds to changes in the inputs of
solar or magnetospheric energy. When upwelling does participate in ion outflow, it can control the flux of
escaping ions by the rate at which it feeds thermal plasma to the higher altitude energization regions. In that
regard, it is important to understand ionospheric upwelling that occurs in places where escaping ions are
generated routinely such as the so-called cleft ion fountain [Lockwood et al., 1985; Valek et al., 2002] and the
dayside auroral zone. Using ion driftmeter and RPA data from several DMSP satellites we demonstrate how
topside plasma upflow on the dayside responds to variations in the solar wind. We have observed that the
intensity of the upflow flux, the location of the upflow region, and the size of the upflow region are highly correlated
with solar wind parameters such as the merging electric field and dynamic pressure.
DE: 2431 Ionosphere/magnetosphere interactions (2736)
DE: 2481 Topside ionosphere
DE: 2704 Auroral phenomena (2407)
DE: 2784 Solar wind/magnetosphere interactions
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting