HR: 15:25h
AN: SM22C-08    [PDF]
TI: A statistical study of the orientation, motion, and thicknesses of density and electric field structures observed by Cluster~II above the auroral accleration region
AU: * Hull, A J
EM: ahull@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California at Berkeley, 7 Gauss Way, Berkeley, CA 94720
AU: Bonnell, J W
EM: jbonnell@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California at Berkeley, 7 Gauss Way, Berkeley, CA 94720
AU: Mozer, F S
EM: fmozer@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California at Berkeley, 7 Gauss Way, Berkeley, CA 94720
AU: Andre, M
EM: Mats.Andre@irfu.se
AF: Swedish Institute of Space Physiscs, Uppsala Division, Box 537, Uppsala, ~ Sweden
AU: Eriksson, A
EM: aie@irfu.se
AF: Swedish Institute of Space Physiscs, Uppsala Division, Box 537, Uppsala, ~ Sweden
AU: Vaivads, A
EM: andris.vaivads@irfu.se
AF: Swedish Institute of Space Physiscs, Uppsala Division, Box 537, Uppsala, ~ Sweden
AU: Pedersen, A
EM: arne.pedersen@fys.uio.no
AF: Dept. of Physics, University of Oslo, P.O. Box 1048, Oslo, ~ Norway
AU: Lindqvist, P
EM: lindqvist@plasma.kth.se
AF: Royal Institute of Technology, Teknikringen 31, Stockholm, ~ Sweden
AU: Laakso, H
EM: harri.laakso@esa.int
AF: Space Science Dept., ESTEC, Noordwijk, ~ Netherlands
AB: We present the results of a statistical study of the properties of electric field and density structures observed by the Cluster~II spacecraft above the auroral acceleration region. Of particular emphasis is the orientation, motion, and thicknesses of time stationary structures. The multi-point electric field and density measurements from the Cluster~II constellation are used to estimate the direction and propagation speed of structures in the electric fields and plasma density (as inferred from spacecraft floating potential measurements), as well as to quantify the thicknesses of those structures. These spatial structures propagate transverse to the magnetic field at speeds of $\sim$10 km/s and are characterized by thicknesses that range from a few hundred kilometers to a few thousand kilometers in extent. Thus with these observations we are probing the high-altitude potential and density structures that are associated with relatively fast (1 km/s) proper motions of fairly large scale (10-100 km) features in the auroral zone. The variation in the properties of these spatial structures with other parameters that characterize the auroral zone, such as altitude, local time, invariant latitude, and geomagnetic activity will also be discussed.
DE: 2704 Auroral phenomena (2407)
DE: 2712 Electric fields (2411)
DE: 2736 Magnetosphere/ionosphere interactions
DE: 2764 Plasma sheet
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting