Entry of plasma sheet particles into the inner magnetosphere as observed by Polar/CAMMICE

NY Ganushkina*, TI Pulkkinen, VA Sergeev, MV Kubyshkina, DN Baker, NE Turner, M Grande, B Kellett, J Fennell, J Roeder, JA Sauvaud, TA Fritz

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Statistical results are presented from Polar/CAMMICE measurements of events during which the plasma sheet ions have penetrated deeply into the inner magnetosphere. Owing to their characteristic structure in energy-time spectrograms, these events are called "intense nose events." Almost 400 observations of such structures were made during 1997. Intense nose events are shown to be more frequent in the dusk than in the dawn sector. They typically penetrate well inside L = 4, the deepest penetration having occurred around midnight and noon. The intense nose events are associated with magnetic (substorm) activity. However, even moderate activity (AE = 150-250 nT) resulted in formation of these structures. In a case study of November 3, 1997, three sequential inner magnetosphere crossings of the Polar and Interball Auroral spacecraft are shown, each of which exhibited signatures of intense nose-like structures. Using the innermost boundary determinations from these observations, it is demonstrated that a large-scale convective electric field alone cannot account for the inward motion of the structure. It is suggested that the intense nose structures are caused by short-lived intense electric fields (in excess of similar to1 mV/m) in the inner tail at L = 4-5.

Original languageEnglish
Pages (from-to)25205-25219
Number of pages15
JournalJournal of Geophysical Research
Volume105
Issue numberA11
Publication statusPublished - 1 Nov 2000
MoE publication typeA1 Journal article-refereed

Keywords

  • ELECTRIC-FIELD
  • RING CURRENT
  • SUBSTORM ONSETS
  • CONVECTION
  • INSTRUMENT
  • SPACECRAFT
  • SATELLITE
  • ONBOARD
  • ORIGIN
  • STORMS

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