Annales Geophysicae
www.ann-geophys.net
0992-7689
1432-0576
26
9
2008
10.5194/angeo-26-2771-2008
http://www.ann-geophys.net/26/2771/2008/
http://www.ann-geophys.net/26/2771/2008/angeo-26-2771-2008.html
http://www.ann-geophys.net/26/2771/2008/angeo-26-2771-2008.pdf
2771
2780
2008-09-17
Conjugate observation of sharp dynamical boundary in the inner magnetosphere by Cluster and DMSP spacecraft and ground network
S. V. Apatenkov
apatenkov@geo.phys.spbu.ru
V. A. Sergeev
O. Amm
W. Baumjohann
R. Nakamura
A. Runov
F. Rich
P. Daly
A. Fazakerley
I. Alexeev
J. A. Sauvaud
Yu. Chotyaintsev
St. Petersburg State University, St. Petersburg, Russia
Finnish Meteorological Institute, Helsinki, Finland
Space Research Institute, Austrian Academy of Sciences, Graz, Austria
Institute of Geophysics and Planetary Physics, UCLA, Los Angeles, CA, USA
AFRL, Hanscom Air Force Base, MA01731, USA
Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany
Mullard Space Science Laboratory, University College London, UK
Centre d'Etude Spatiale des Rayonnements, Toulouse, France
Swedish Institute of Space Physics, Uppsala, Sweden
We investigate an unusual sharp boundary separating two plasma populations
(inner magnetospheric plasma with high fluxes of energetic particles and
plasma sheet) observed by the Cluster quartet near its perigee on 16 December 2003.
Cluster was in a pearl-on-string configuration at 05:00 MLT and mapped along
magnetic field lines to ~8–9 <I>R<sub>E</sub></I> in the equatorial plane. It was
conjugate to the MIRACLE network and the DMSP F16 spacecraft passed close to
Cluster footpoint. The properties of the sharp boundary, repeatedly crossed 7
times by five spacecraft during ~10 min, are: (1) upward FAC sheet
at the boundary with ~30 nA/m<sup>2</sup> current density at Cluster and
~2000 nA/m<sup>2</sup> at DMSP; (2) the boundary had an embedded layered
structure with different thickness scales, the electron population transition
was at ~20 km scale at Cluster (<7 km at DMSP), proton population had
a scale ~100 km, while the FAC sheet thickness was estimated to be
~500 km at Cluster (~100 km at DMSP); (3) the boundary propagated
in the earthward-eastward direction at ~8 km/s in situ
(equatorward-eastward ~0.8 km/s in ionosphere), and then decelerated
and/or stopped. We discuss the boundary formation by the collision of two
different plasmas which may include dynamical three-dimensional field-aligned
current loops.
Amm, O. and Viljanen, A.: Ionospheric disturbance magnetic field continuation from the ground to the ionosphere using spherical elementary current systems, Earth, Planets Space, 51, 431–440, 1999.
Amm,~O., Aksnes,~A., Stadsnes,~J., Ostgaard,~N., Vondrak,~R R., Germany,~G A., Lu,~G., and Viljanen,~A.: Mesoscale ionospheric electrodynamics of omega bands determined from ground-based electromagnetic and satellite optical observations, Ann. Geophys., 23, 325–342, 2005.
Angelopoulos,~V.,~Baumjohann, W.,~Kennel, C F.,~Coroniti, F V., et al.: Bursty bulk flows in the inner central plasma sheet, J. Geophys. Res., 97, 4027–4039, 1992.
Balogh,~A., Carr,~C M., Acuna,~M H., et~al.: The Cluster magnetic field investigations: overview of in-flight performance and initial results, Ann. Geophys., 19, 1207–1217, 2001.
Friedel,~R H W., Korth,~H., Henderson,~M G., Thomsen,~M F., and Scudder,~J D.: Plasma sheet access to the inner magnetosphere, J. Geophys. Res., 106(A4), 5845–5858, 2001.
Gustafsson,~G., Andre,~M., Carozzi,~T., et al.: First results of electric field and density observations by Cluster EFW based on initial months of operation, Ann. Geophys., 19, 1219–1240, 2001.
Henderson,~M G.,Kepko,~L., Spence,~H E., Connors,~M., Sigwarth,~J B., Frank,~L A., Singer~H J., and Yumoto,~K.: The Evolution of North-South Aligned Auroral Forms into Auroral Torch Structures: The Generation of Omega Bands and Ps6 Pulsations via Flow Bursts, Proc. Sixth International Conference on Substorms, Seattle, 25–29 March 2002, edited by: Winglee, R. M., 169–174, University of Washington press, 2002.
Johnstone,~A D., Alsop,~C., Burge,~S., et al.: Peace: a Plasma Electron and Current Experiment, Space Sci. Rev., 79, 351–398, 1997.
Rème,~H., Aoustin,~C., Bosqued,~J M., et al.: First multispacecraft ion measurements in and near the Earth's magnetosphere with the identical Cluster ion spectrometry (CIS) experiment, Ann. Geophys., 19, 1303–1354, 2001.
Rich, F J., Hardy, D A., and Gussenhoven, M S.: Enhanced ionosphere-magnetosphere data from the DMSP satellites, EOS Trans. AGU, 66, 513, 1985.
Sergeev,~V A., Sauvaud,~J.-A., Popescu,~D., Kovrazhkin,~R A., Liou,~K., Newell,~P T., Brittnacher,~M., Parks,~G., Nakamura,~R., Mukai,~T., and Reeves,~G D.: Multiple-spacecraft observation of a narrow transient plasma jet in the Earth’s plasma sheet, Geophys. Res. Lett., 27(6), 851–854, doi:10.1029/1999GL010729, 2000.
Sergeev, V A., Sauvaud, J.-A., Reme, H., Balogh, A., Daly, P., Zong, Q.-G., Angelopoulos, V., Andre, M., and Vaivads, A.: Sharp boundary between the inner magnetosphere and active outer plasma sheet, Geophys. Res. Lett., 30(15), 1799, doi:10.1029/2003GL017095, 2003.
Sergeev, V A., Liou,~K, Newell,~P T., Ohtani,~S.-I., Hairston,~M R., and Rich, F.: Auroral streamers: characteristics of associated precipitation, convection and field-aligned currents, Ann. Geophys., 22, 537–548, 2004.
Sergeev,~V A., Yahnin,~D A., Liou,~K., Thomsen,~M F., and Reeves,~G D.: Narrow Plasma Streams as a candidate to populate the inner magnetosphere, Geophysical Monograph Series, p.155, 2005.
Syrjäsuo,~M., Pulkkinen, T I., Pellinen,~R J., Janhunen,~P., Kauristie,~K., Viljanen,~A., Opgenoorth,~H J., Karlsson,~P., Wallman,~S., Eglitis,~P., Amm,~O., Nielsen,~E., and Thomas,~C.: Observations of substorm electrodynamics using the MIRACLE network, Proc. Fourth International Conference on Substorms(ICS-4), Lake Hamana, Japan, 9–13 March 1998.
Takada,~T., Nakamura,~R., Baumjohann,~W., Asano,~Y., Volwerk,~M., Zhang,~T L., Klecker,~B., Rème,~H., Lucek,~E A., and Carr,~C.: Do BBFs contribute to inner magnetosphere dipolarizations: Concurrent Cluster and Double Star observations, Geophys. Res. Lett., 32, L21109, doi:10.1029/2006GL027440, 2006.
Tsyganenko,~N A.: A magnetospheric magnetic field with a warped tail current sheet, Planet. Space Sci., 37, 5–20, 1989.
Untiedt, J. and Baumjohann, W.: Studies of polar current systems using the IMS Scandinavian Magnetometer Array. Space Sci. Rev., 63, 245–390, 1993.
Wilken,~B., Daly,~P W., Mall,~U., et~al.: First results from the RAPID imaging energetic particle spectrometer on board Cluster, Ann. Geophys., 19, 1355–1366, 2001.