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Ohtani et al. 1988
Ohtani, S., Kokubun, S., Elphic, R.C. and Russell, C.T. (1988). Field-aligned current signatures in the near-tail region 1. ISEE observations in the plasma sheet boundary layer. Journal of Geophysical Research 93: doi: 10.1029/88JA00443. issn: 0148-0227.

Signatures of field-aligned current in the near-tail region are examined by using ISEE magnetometer data. We focus our attention on steplike changes of magnetic field direction, which are interpreted as the spacecraft crossing of field-aligned current sheets. Individual case studies of two substorms on March 22, 1979 (CDAW 6 events), indicate that the field-aligned current signatures in the near-tail region are consistent with observations at lower altitudes and that the currents in the plasma sheet boundary layer can be identified as parts of the large-scale current system, the region 1 system. Statistical properties of the field-aligned currents are also studied. Earthward and tailward currents tend to be observed in postmidnight and in premidnight, respectively, as expected from the distribution of current direction in the region 1 system. The present result seems to be inconsistent with that of Elphic et al. (1985). This apparent discrepancy is due to the difference in identification of field-aligned currents signatures. They have analyzed field-aligned currents at the edge of the plasma sheet boundary layer, while we examine large-scale currents in the present analysis. It is thus suggested that small-scale field-aligned currents with opposite polarities are imbedded poleward of the region 1 system. The results of these two studies are considered to be complementary to each other. The dependence of the current intensity on the geomagnetic activity and the radial distance from the Earth indicates that there are two field-aligned current sources in the magnetotail. One is in the region RXY =(X 2GSM+Y 2GSM)1/2≥15 Re, and the other is nearer to the Earth, RXY<15Re. The distant current source persistently exists and the current intensity is almost independent of the activity of the magnetosphere. On the other hand, the near-earth current source plays an active role during substorms. ¿ American Geophysical Union 1988

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Abstract

Keywords
Magnetospheric Physics, Current systems, Magnetospheric Physics, Magnetotail boundary layers, Magnetospheric Physics, Storms and substorms
Journal
Journal of Geophysical Research
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Publisher
American Geophysical Union
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