Ionospheric response to the CME passage of September 24, 1998

P. Craven1, (256-544-7639;, J. Spann1, (256-544-5339;,
M. Chandler1, (256-544-7645), G. Germany2, T. Moore3


1. NASA/Marshall Space Flight Center Space Sciences Lab. ES83, Huntsville, AL 35812, United States

2. Center for Space Plasma and Aeronomy Research, The University of Alabama in Huntsville, Huntsville, AL 35899, United States

3. NASA/Goddard Space Flight Center Interplanetary Physics Branch Code 692, Greenbelt, MD 20771, United States


On September 24, 1998, a solar coronal mass ejection struck the Earth's magnetosphere. The magnetosphere/ionosphere system exhibited a response in several ways one of which was an increase in ion outflow from the ionosphere, ionosphereic mass ejections in response to the pressure pulse from the shock passage at the front of the magnetosphere [Moore et al., 1998]. However, the timing of the incidence of the pressure pulse and the ionsopheric response has not been examined in detail. Images from the Ultraviolent Imager show a brightening in the dayside aurora at the same time the shock is seen at Polar at about 23:45 UT on the 24th. . We examine the temporal and spatial relationship (using simple models ) of these two events to determine the correlation of the particles seen at Polar and the regions of increased energy input seen in the aurora and discuss the physical implications of the results.