Published in

Wiley, Journal of Geophysical Research. Space Physics, 12(119), p. 9714-9728

DOI: 10.1002/2014ja020522

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Event study combining magnetospheric and ionospheric perspectives of the substorm current wedge modeling

This paper is available in a repository.
This paper is available in a repository.

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Data provided by SHERPA/RoMEO

Abstract

Unprecedented spacecraft and instrumental coverage and the isolated nature and distinct step-like development of a substorm on 17 March 2010 has allowed validation of the two-loop substorm current wedge model (SCW2L). We find a close spatio-temporal relationship of the SCW with many other essential signatures of substorm activity in the magnetotail and demonstrate its azimuthally localized structure and step-wise expansion in the magnetotail. We confirm that ground SCW diagnostics makes it possible to reconstruct and organize the azimuthal spatio-temporal substorm development pattern with accuracy better than 1 h MLT in the case of medium-scale substorm. The AMPERE-based study of global field-aligned current distribution indicates that: (a) the SCW-related FAC system consists of simultaneously activated R1- and R2-type currents; (b) their net currents have a R1-sense; and (c) locations of net current peaks are consistent with the SCW edge locations inferred from midlatitude variations. Thanks to good azimuthal coverage of four GOES and three THEMIS spacecraft, we evaluated the intensities of the SCW R1- and R2-like current loops (using the SCW2L model) obtained from combined magnetospheric and ground midlatitude magnetic observations and found the net currents consistent (within a factor of 2) with the AMPERE-based estimate. We also ran an adaptive magnetospheric model and show that SCW2L model outperforms it in predicting the magnetic configuration changes during substorm dipolarizations.