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|Title:||Simultaneous ground-satellite observations of meso-scale auroral arc undulations|
Milan, S. E.
|Publisher:||American Geophysical Union (AGU); Wiley|
|Citation:||Journal of Geophysical Research A: SPACE PHYSICS, 2012, 117 (6)|
|Abstract:|| We present simultaneous ground-based and in situ measurements of a train of meso-scale (about 100–300 km) auroral arc undulations, occurring in the postmidnight sector (∼1 MLT) between 0040 UT and 0054 UT on September 21, 2009. The undulations appeared at the auroral poleward boundary, and then moved eastward with a speed of 0.9–2.2 km s−1. Dynamic behaviors of the associated meso-scale ionospheric plasma flows and current systems were also detected with the ground-based magnetometer and radar measurements within the all-sky camera field-of-view. During the interval of interest, simultaneous Cluster observations in the central near tail region (11–14 RE down tail) were available, and especially the ionospheric footprint of Cluster 2 (CL2) was close to the optical auroral forms. CL2 observed strong fluctuations in the in situ magnetic field with amplitude of 5–10 nT whenever a bright arc area, and its trailing adjacent area, of the auroral undulations passed its ionospheric footprint. Such in situ magnetic field changes at CL2 could be considered as a manifestation of localized upward and downward field-aligned current sheets moving eastward at the central near-Earth tail boundary, linked to the meso-scale auroral undulation structures.|
|Rights:||Copyright © 2012 by the American Geophysical Union. All rights reserved. Archived with reference to Usage Permissions granted to authors, available at http://publications.agu.org/author-resource-center/usage-permissions/|
|Appears in Collections:||Published Articles, Dept. of Physics and Astronomy|
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