Wave characteristics of daytime and nighttime Pi 2 pulsations at the equatorial and low latitudes

M. Shinohara, K. Yumoto, A. Yoshikawa, O. Saka, S. I. Solovyev, E. F. Vershinin, N. B. Trivedi, J. M. Da Costa

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34 Citations (Scopus)

Abstract

Peculiarities of daytime and nighttime Pi 2 pulsations at the dip equator are examined by using multipoint measurements from the 210° magnetic meridian (MM) magnetometer network. We found that during daytime the amplitude of Pi 2 pulsations at the dip equator is enhanced, and the phase lags ∼ 34° behind those at low-latitude (magnetic latitude Φ = 19.5-46.2°) stations. On the other hand, during nighttime the amplitude of Pi 2 pulsations at the dip equator is depressed, and the phase lags ∼ 18° behind those at the lower latitudes. Because the zonal ionospheric conductivity at the dip equator is much higher than that at the off-dip equator region, Pi 2 signals are expected to be distorted more effectively at the dip equator. The observations imply that the daytime and nighttime Pi 2 pulsations in the equatorial and low-latitude regions can be explained by invoking an instantaneous penetration of electric field variations from the nightside polar ionosphere to the dayside equatorial ionosphere, and a direct incidence of compressional oscillations from the nightside inner magnetosphere, respectively.

Original languageEnglish
Article number97GL02146
Pages (from-to)2279-2282
Number of pages4
JournalGeophysical Research Letters
Volume24
Issue number18
DOIs
Publication statusPublished - 1997

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Earth and Planetary Sciences(all)

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