Observations of an active thin current sheet
2008 (English)In: Journal of Geophysical Research, ISSN 0148-0227, Vol. 113, no A7, A07S27- p.Article in journal (Refereed) Published
We analyze observations of magnetotail current sheet dynamics during a substorm between 2330 and 2400 UT on 28 August 2005 when Cluster was in the plasma sheet at [-17.2, -4.49, 0.03] R-E (GSM) with the foot points near the IMAGE ground-based network. Observations from the Cluster spacecraft, ground-based magnetometers, and the IMAGE satellite showed that the substorm started in a localized region near midnight, expanding azimuthally. A thin current sheet with a thickness of less than 900 km and current density of about 30 nA/m(2) was observed during 5 min around the substorm onset. The thinning of the current sheet was accompanied by tailward plasma flow at a velocity of -700 km/s and subsequent reversal to earthward flow at V-x approximate to 500 km/s coinciding with a B-z turning from -5 to + 10 nT. The analysis of magnetic and electric fields behavior and particle distributions reveals signatures of impulsive (with similar to 1 min timescale) activations of the thin current sheet. These observations were interpreted in the framework of transient reconnection, although the data analysis reveals serious disagreements with the classical 2.5-D X line model.
Place, publisher, year, edition, pages
2008. Vol. 113, no A7, A07S27- p.
IdentifiersURN: urn:nbn:se:uu:diva-149355DOI: 10.1029/2007JA012685ISI: 000257801200001OAI: oai:DiVA.org:uu-149355DiVA: diva2:404692