Variations of low-latitude geomagnetic fields and Dst index caused by magnetospheric substorms

Chao Song Huang, J. C. Foster, L. P. Goncharenko, G. D. Reeves, J. L. Chau, K. Yumoto, K. Kitamura

Research output: Contribution to journalArticlepeer-review

49 Citations (Scopus)

Abstract

We present observations of periodic magnetospheric substorms and corresponding ionospheric disturbances. Since the periodic substorms occur during a stable interplanetary magnetic field, we are able to identify which ionospheric signatures are caused solely by substorms. We find that the low-latitude ionospheric electric field perturbation after substorm onsets is eastward on the dayside and westward on the nightside and that the ground magnetometer northward (H) deviations at middle and low latitudes show an increase (a positive bay) after each substorm onset, no matter whether the magnetometers are located on the dayside or on the nightside. The nightside magnetometer H deviations are closely correlated with the inner magnetospheric magnetic field Bz component during the dipolarization process. The Dst index shows a significant increase of 20-40 nT after each substorm onset. We propose that the increase in the magnetometer H field and Dst index in response to substorm onsets is related to the field dipolarization. In this scenario the nightside magnetosphere earthward of the near-Earth neutral line is highly compressed during the dipolarization, and the magnetic flux density within the inner magnetosphere is greatly enhanced, resulting in an increase in the ground magnetometer H component and in Dst.

Original languageEnglish
Article numberA05219
JournalJournal of Geophysical Research: Space Physics
Volume109
Issue numberA5
DOIs
Publication statusPublished - May 2004

All Science Journal Classification (ASJC) codes

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

Fingerprint Dive into the research topics of 'Variations of low-latitude geomagnetic fields and Dst index caused by magnetospheric substorms'. Together they form a unique fingerprint.

Cite this