Open AccessSpace Technology 5 multipoint observations of temporal and spatial variability of field‐aligned currents
Author(s) -
Le G.,
Wang Y.,
Slavin J. A.,
Strangeway R. J.
Publication year - 2009
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2009ja014081
Subject(s) - mesoscale meteorology , electric field , physics , current (fluid) , spacecraft , computational physics , geophysics , magnetic field , field (mathematics) , earth's magnetic field , temporal resolution , meteorology , astronomy , optics , mathematics , quantum mechanics , pure mathematics , thermodynamics
Space Technology 5 (ST5) is a constellation mission consisting of three microsatellites. It provides the first multipoint magnetic field measurements in low Earth orbit, which enables us to separate spatial and temporal variations. In this paper, we present a study of the temporal variability of field‐aligned currents using the ST5 data. We examine the field‐aligned current observations during and after a geomagnetic storm and compare the magnetic field profiles at the three spacecraft. The multipoint data demonstrate that mesoscale current structures, commonly embedded within large‐scale current sheets, are very dynamic with highly variable current density and/or polarity in ∼10 min time scales. On the other hand, the data also show that the time scales for the currents to be relatively stable are ∼1 min for mesoscale currents and ∼10 min for large‐scale currents. These temporal features are very likely associated with dynamic variations of their charge carriers (mainly electrons) as they respond to the variations of the parallel electric field in auroral acceleration region. The characteristic time scales for the temporal variability of mesoscale field‐aligned currents are found to be consistent with those of auroral parallel electric field.