HR: 15:34h
AN: SM53C-05    [Abstracts]
TI: Cluster measurements of the divergence of the electron pressure tensor and J×B: Relative contributions to Ohm's law
AU: Henderson, P D
EM: pdh@mssl.ucl.ac.uk
AF: Mullard Space Science Laboratory, University College London, Dorking, RH5 6NT, United Kingdom
AU: * Owen, C
EM: cjo@mssl.ucl.ac.uk
AF: Mullard Space Science Laboratory, University College London, Dorking, RH5 6NT, United Kingdom
AU: Lahiff, A
EM: adl@mssl.ucl.ac.uk
AF: Mullard Space Science Laboratory, University College London, Dorking, RH5 6NT, United Kingdom
AU: Alexeev, I
EM: ia@mssl.ucl.ac.uk
AF: Mullard Space Science Laboratory, University College London, Dorking, RH5 6NT, United Kingdom
AU: Fazakerley, A
EM: anf@mssl.ucl.ac.uk
AF: Mullard Space Science Laboratory, University College London, Dorking, RH5 6NT, United Kingdom
AU: Stenberg, G
EM: gabriella@irfu.se
AF: Swedish Institute of Space Physics, Uppsala, Sweden
AU: Lucek, E
EM: e.lucek@imperial.ac.uk
AF: Space and Atmospheric Physics, Imperial College London, London, SW7 2BZ, United Kingdom
AU: Reme, H
EM: Henri.Reme@cesr.fr
AF: Centre d'Etude Spatiale des Rayonnements, Toulouse, France
AB: On the 17th August 2003 Cluster observed a flow reversal in the tail plasma sheet, consistent with the passage of a reconnection X-line. Henderson et al. (2006) have investigated the divergence of the observed electron pressure tensor, derived solely from measurements measured from the PEACE electron spectrometer instruments on each of the 4 Cluster spacecraft, during a current sheet crossing in this period. This calculation is possible when the spacecraft are in burst mode and carefully calibrated, full 3D particle distributions can be used to determine the electron moments. The Curlometer technique, applied to data from the Cluster magnetometers, was used to assess J×B, and thus the relative contributions of the electron pressure divergence and Hall terms in the generalised Ohm's law were determined. An anti-correlation between these two terms in the component normal to the current sheet was reported. In this paper we report an extension to Henderson et al.'s (2006) case study, in which we investigate the generality of those results by investigating further current sheet crossings which occurred on the 17th August 2003, as well as a number of additional periods of burst mode data available from the 2003 tail season. Data from this period are particularly useful for this study as the inter- spacecraft separations are at their smallest for the Cluster mission. We confirm the generality of the observed anti-correlation between the Hall and electron pressure tensor divergence terms in Ohm's law, and consider the theoretical background in an attempt to explain the relative magnitude of their contributions to the total electric field. Henderson et al., "Cluster PEACE observations of electron pressure tensor divergence in the magnetotail", Geophys, Res, Lett. (2006), 33, L22106
DE: 2712 Electric fields (2411)
DE: 2721 Field-aligned currents and current systems (2409)
DE: 2764 Plasma sheet
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Joint Assembly