University of Oulu

Pedersen, M. N., Vanhamäki, H., Aikio, A. T., Waters, C. L., Gjerloev, J. W., Käki, S., & Workayehu, A. B. (2022). Effect of ICME-driven storms on field-aligned and ionospheric currents from AMPERE and SuperMAG. Journal of Geophysical Research: Space Physics, 127, e2022JA030423.

Effect of ICME-driven storms on field-aligned and ionospheric currents from AMPERE and SuperMAG

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Author: Pedersen, M. N.1; Vanhamäki, H.1; Aikio, A. T.1;
Organizations: 1Space Physics and Astronomy Research Unit, University of Oulu, Oulu, Finland
2School of Mathematical and Physical Sciences, University of Newcastle, Callaghan, NSW, Australia
3The Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
4Faculty for Physics and Technology, University of Bergen, Bergen, Norway
5Finnish Meteorological Institute, Helsinki, Finland
6Division of Particle Physics and Astrophysics, University of Helsinki, Helsinki, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 10.4 MB)
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Language: English
Published: American Geophysical Union, 2022
Publish Date: 2022-09-22


This study investigates the field-aligned currents (FACs) and ionospheric equivalent currents for interplanetary coronal mass ejection (ICME)-driven storms by considering 45 events with a minimum Dst ≤ −50 nT. The FACs and ionospheric equivalent currents are studied by applying a superposed epoch analysis to data from AMPERE and SuperMAG with the zero epoch (t₀) centered at the onset of the storm main phase. The currents and number of substorm onsets begin to increase 3 hr before t0 and maximizes about 1 hr after t₀. The currents and number of substorm onsets remain high throughout the entire storm main phase, until at t₀ + 14 hr they start to slowly relax back to quiet time conditions. The storms were separated into two groups based on the solar wind dynamic pressure pddyn around t₀. High pdyn storms are mostly driven by the sheath region ahead of the ejecta. These storms have short main phase durations and larger currents early in the main phase which maximize at t₀ + 50 min. The low pdyn group contains storms that start during the magnetic clouds (MC) and have gradually increasing currents that maximize at t₀ + 11 hr, close to the end of the storm main phase. For the first 4 hr of the storm main phase, the currents in sheath-driven storms are larger than for MC-driven storms. The Russell-McPherron effect is less important for ICME-driven storms where only 44% have a contribution, compared to 82% of high speed stream/stream interaction driven storms.

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Series: Journal of geophysical research. Space physics
ISSN: 2169-9380
ISSN-E: 2169-9402
ISSN-L: 2169-9380
Volume: 127
Issue: 8
Article number: e2022JA030423
DOI: 10.1029/2022ja030423
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Funding: This work was supported by the Academy of Finland project 314664 and 314670. We thank the AMPERE team and the AMPERE Science Center for providing the Iridium derived data products ( For the ground magnetometer data and substorm onset list, we gratefully thank the SuperMAG collaboration and all organizations involved ( For the geomagnetic indices, solar wind and interplanetary magnetic field data, we gratefully thank NASA/GSFC's Space Physics Data Facility's OMNIWeb (
Academy of Finland Grant Number: 314664
Detailed Information: 314664 (Academy of Finland Funding decision)
Copyright information: © 2022. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.