HR: 1400h
AN: SM33A-07    [Abstracts]
TI: Cluster Observations of High-Altitude Controllers and Consequences of Auroral Acceleration Region Formation
AU: * Hull, A J
EM: ahull@ssl.berkeley.edu
AF: Space Sciences Laboratory, UC Berkeley, 7 Gauss Way, Berkeley, CA 94720, United States
AU: Wilber, M
EM: wilber@ssl.berkeley.edu
AF: Space Sciences Laboratory, UC Berkeley, 7 Gauss Way, Berkeley, CA 94720, United States
AU: Bonnell, J W
EM: jbonnell@ssl.berkeley.edu
AF: Space Sciences Laboratory, UC Berkeley, 7 Gauss Way, Berkeley, CA 94720, United States
AU: Mozer, F
EM: fmozer@ssl.berkeley.edu
AF: Space Sciences Laboratory, UC Berkeley, 7 Gauss Way, Berkeley, CA 94720, United States
AU: Chaston, C
EM: ccc@ssl.berkeley.edu
AF: Space Sciences Laboratory, UC Berkeley, 7 Gauss Way, Berkeley, CA 94720, United States
AU: McFadden, J
EM: mcfadden@ssl.berkeley.edu
AF: Space Sciences Laboratory, UC Berkeley, 7 Gauss Way, Berkeley, CA 94720, United States
AU: Goldstein, M
EM: melvyn.l.goldstein@nasa.gov
AF: NASA Goddard Space Flight Center, Code 692, Greenbelt, MD 20771, United States
AU: Fillingim, M
EM: matt@ssl.berkeley.edu
AF: Space Sciences Laboratory, UC Berkeley, 7 Gauss Way, Berkeley, CA 94720, United States
AB: The auroral acceleration region is an integral part of the magnetosphere-ionosphere electrodynamic system, and plays a key role in the transport of energy and particles between space and Earth. Processes occurring therein have received considerable attention over the past few decades, however much of this attention was based on a quasistatic interpretation of the data. To date, very little is known in-situ about the time development of the plasma and fields within and above the auroral acceleration region, which we address here. We present detailed plasma and fields measured by Cluster at high-altitude (> 3 R_E) within and above examples of co-evolving upward and downward auroral acceleration systems, occurring during differing magnetospheric conditions. In particular, we highlight the developmental sequence of auroral potentials and reconfigurations of Earth's magnetotail topology, as well as specific orderings for the growth of associated currents, electric fields, density cavities, and plasma constituents that transpire within these systems, with the aim of identifying dominant controlling factors, and assessing consequences. Preliminary results indicate the importance of the temperature of injected electrons in controlling the development of acceleration potentials, with density cavitation being a consequence of an erosion (or acceleration) of cold dense plasma, as opposed to variations in the source electron density. Comparisons with Images from Polar-UVI and IMAGE data show that the developing arc systems presented here lead to localized auroral intensifications, which may or may not have periodic occurrences, with scales and motion that are consistent with these high-altitude measurements.
DE: 2431 Ionosphere/magnetosphere interactions (2736)
DE: 2451 Particle acceleration
DE: 2704 Auroral phenomena (2407)
DE: 2721 Field-aligned currents and current systems (2409)
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Joint Assembly