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Laboratory for Atmospheric and Space Physics

Global coherence of electron enhancements in the magnetosphere

September 24, 2012

Several magnetic cloud/CME events have been observed during the 1997-98 time period, as we approach the maximum of the next solar cycle. Multiple spacecraft have observed for the first time the evolution of these events from their origin to passage over the magnetosphere. We have studied the magnetospheric outer zone energetic electron response to these cloud/CME events using data from sensors onboard SAMPEX and POLAR. Daily overview plots for 1997 are shown in the accompanying figure. In the figure, the May 15, 1997 CME impact on the magnetosphere stands out clearly; this energization caused a factor of 10 increase in NOx compounds in the upper atmosphere (Callis et al., J. Geophys. Res., 1998, in press). =20

SAMPEX and POLAR measure electrons in energy range of several kev to MeV over all L shells at 2-9 RE and 600 km altitudes respectively. Data from the WIND spacecraft serves to identify the cloud/CME events. We have compared the energetic electron responses at different L shells, energies and altitudes. Superposed epoch analyses were done to examine the common features of the outer zone electron response. These results demonstrate a remarkable coherence of energetic electron enhancements throughout the entire outer radiation zone.

Contributed by Shri Kanekal, RSTX/NASA GSFC

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