Observation of an inner magnetosphere electric field associated with a BBF-like flow and PBIs
1Laboratory for Atmospheric and Space Physics, University of Colorado at Boulder, CO, USA
2Space Sciences Laboratory, University of California, Berkeley, CA, USA
3Swedish Institute of Space Physics, Uppsala, Sweden
4Department of Physics and Astronomy, University of Calgary, Calgary, Canada
5Space Science Center and Physics Department, University of New Hampshire, Durham, NH, USA
6Department of Astrophysical and Planetary Sciences, University of Colorado at Boulder, CO, USA
7IGPP/ESS, University of California, Los Angeles, CA , USA
8Institute for Geophysics and Meteorology, Technical University of Braunschweig, Braunschweig, Germany
9Department of Physics, University of Alberta, Edmonton, Canada
Abstract. Themis E observed a perpendicular (to the magnetic field) electric field associated with an Earthward plasma flow at XGSM=−9.6 RE on 11 January 2008. The electric field observation resembles Cluster observations closer to Earth in the auroral region. The fast plasma flow shared some characteristics with bursty bulk flows (BBFs) but did not meet the usual criteria in maximum velocity and duration to qualify as one. Themis C observed the same flow further downtail but Themis D, separated by only 1 RE in azimuthal direction from Themis E, did not. At the time of the electric field and ion flow event, the all-sky imager and ground-based magnetometer at Rankin Inlet observed Poleward Boundary Intensifications (PBIs) and a negative bay signature. None of the other Themis ground-based observatories recorded any significant auroral or magnetic field activity, indicating that this was a localized activity. The joint Themis in situ and ground-based observations suggest that the two observations are related. This indicates that auroral electric fields can extend to regions much farther out than previously seen in Cluster observations.
Johansson, T., Bonnell, J. W., Cully, C., Donovan, E., Raeder, J., Eriksson, S., Andersson, L., Ergun, R. E., Angelopoulos, V., McFadden, J., Glassmeier, K.-H., and Mann, I.: Observation of an inner magnetosphere electric field associated with a BBF-like flow and PBIs, Ann. Geophys., 27, 1489-1500, doi:10.5194/angeo-27-1489-2009, 2009.