Signature of electric field associated with localized electron precipitation in the polar cap region-akebono (EXOS-D) results-

T. Obara, T. Mukai, H. Hayakawa, K. Tsuruda, A. Matsuoka, A. Nishida

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Akebono (EXOS-D) observations demonstrated that the electric field in the polar cap region is very irregular and electron precipitation spikes are prevalent when the interplanetary magnetic field (IMF) is directed northward. Comparison of the electric field and the particle precipitation shows that most electron precipitations occur in the divE< 0 regions. The variation of the electric field was predominantly seen in the dawn-to-dusk (Ey) component rather than in the noon-midnight (E-4) component, when the observations were made in the nightside polar cap region. This means that the particle precipitation region is basically sun-aligned in the nightside polar cap region. However, in the dayside polar cap region, the contribution of the Ex component to div£ is larger, which suggests that the orientation of the elongation is not exactly sun-aligned but also has a zonal component on the dayside. The average energy of the precipitating electrons was in a range from 100 eV to 200 eV. The magnetosheath/mantle is the likely source region of the precipitating electrons in the polar cap during northward IMF conditions.

Original languageEnglish
Pages (from-to)327-335
Number of pages9
Journaljournal of geomagnetism and geoelectricity
Volume48
Issue number3
DOIs
Publication statusPublished - 1996 Jan 1
Externally publishedYes

ASJC Scopus subject areas

  • Environmental Science(all)
  • Earth and Planetary Sciences(all)

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