Space Sciences Laboratory, University of California, Berkeley
Correlations between global auroral images and in-situ measurements in the plasma sheet and magnetotail have led to many new insights into how the magnetosphere and ionospheric auroral region are coupled. Several studies have shown that intense auroral emission in the ionosphere is well correlated with large ion velocity moments, enhancements in the energetic ion and electron fluxes, increases in plasma temperature, and high frequency fluctuations in the magnetic field measured in the plasma sheet. In addition global images provide unambiguous timing of auroral brightenings and direction and speed of propagation of auroral forms. The timing and propagation determined from images, in turn, can be used to put the plasma sheet observations in context. In this presentation, we focus on one particular conjunction of global auroral images and in-situ plasma sheet plasma and magnetic field measurements. Global auroral images from both the Polar UVI and IMAGE FUV instruments show multiple intensifications at different latitudes and local times over the course of a few hours following a solar wind pressure pulse and southward turning of the interplanetary magnetic field. The Cluster spacecraft were located in the plasma sheet at ~ 20 RE. Cluster observations show complex and dynamic plasma behavior and current sheet structure developing a few minutes after the onset of the auroral intensifications. Initial analyses indicate that strong spatial gradients and plasma boundaries are present and that multiple current sheets or boundary waves develop. A kinetic interpretation will be presented to accurately describe the plasma dynamics of the complex nature of plasma sheet observations during auroral activity.
PDF presentation (4.3 MB)
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