Reconciliation of the substorm onset determined on the ground and at the Polar spacecraft

Research output: Contribution to journalArticleScientificpeer-review

Researchers

  • PK Toivanen
  • DN Baker
  • WK Peterson
  • HJ Singer
  • NE Turner
  • H. Li
  • K Kauristie
  • M Syrjäsuo
  • A Viljanen
  • Tuija Pulkkinen

  • A Keiling
  • JR Wygant
  • CA Kletzing

Research units

  • University of Colorado Boulder
  • Lockheed Martin Space Sci Lab, Lockheed Martin
  • NOAA
  • Finnish Meteorological Institute
  • Univ Minnesota, University of Minnesota System, University of Minnesota Twin Cities, Sch Phys & Astron
  • University of Iowa

Abstract

An isolated substorm on Oct. 17, 1997 during a close conjunction of the Polar spacecraft and the ground-based MIRACLE network is studied in detail. We identify signatures of substorm onset in the plasma sheet midway between the ionosphere and the equatorial plasma sheet, determine their timing relative to the ground signatures, and discuss their counterparts on the ground and in the equatorial plasma sheet. The substorm onset is determined as the negative bay onset at 2040:42(+/- 5 sec) UT coinciding with the onset of auroral precipitation, energization of plasma sheet electrons at Polar, and strong magnetic field variations perpendicular to the ambient field. Such accurate timing coincidence is consistent with the Alfven transit time between Polar and the ionosphere. Furthermore, the timing of other field and particle signatures at Polar showed clear deviations from the onset time (+/- 2 min). This suggests that the sequence of these signatures around the onset time can be used to validate the signatures predicted by various substorm onset models.

Details

Original languageEnglish
Pages (from-to)107-110
Number of pages4
JournalGeophysical Research Letters
Volume28
Issue number1
Publication statusPublished - 1 Jan 2001
MoE publication typeA1 Journal article-refereed

    Research areas

  • INSTRUMENT, PARTICLE, MISSION, MODEL

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