Global Empirical Picture of Magnetospheric Substorms Inferred From Multimission Magnetometer Data

G. K. Stephens, M. Sitnov, H. Korth, N. A. Tsyganenko, S. Ohtani, M. Gkioulidou, A. Y. Ukhorskiy

Research output

8 Citations (Scopus)

Abstract

Magnetospheric substorms represent key explosive processes in the interaction of the Earth's magnetosphere with the solar wind, and their understanding and modeling are critical for space weather forecasting. During substorms, the magnetic field on the nightside is first stretched in the antisunward direction and then it rapidly contracts earthward bringing hot plasmas from the distant space regions into the inner magnetosphere, where they contribute to geomagnetic storms and Joule dissipation in the polar ionosphere, causing impressive splashes of aurora. Here we show for the first time that mining millions of spaceborne magnetometer data records from multiple missions allows one to reconstruct the global 3-D picture of these stretching and dipolarization processes. Stretching results in the formation of a thin (less than the Earth's radius) and strong current sheet, which is diverted into the ionosphere during dipolarization. In the meantime, the dipolarization signal propagates further into the inner magnetosphere resulting in the accumulation of a longer lived current there, giving rise to a protogeomagnetic storm. The global 3-D structure of the corresponding substorm currents including the substorm current wedge is reconstructed from data.

Original languageEnglish
Pages (from-to)1085-1110
Number of pages26
JournalJOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
Volume124
Issue number2
DOIs
Publication statusPublished - 1 Feb 2019

Scopus subject areas

  • Forestry
  • Aquatic Science
  • Soil Science
  • Water Science and Technology
  • Earth-Surface Processes
  • Geochemistry and Petrology
  • Geophysics
  • Oceanography
  • Paleontology
  • Ecology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Atmospheric Science

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