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A system science methodology develops a new composite highly predictable index of magnetospheric activity for the community: the whole-Earth index E(1)

Borovsky, Joseph E; Lao, Christian J; (2023) A system science methodology develops a new composite highly predictable index of magnetospheric activity for the community: the whole-Earth index E(1). Frontiers in Astronomy and Space Sciences , 10 10.3389/fspas.2023.1214804. Green open access

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Abstract

For community use, a new composite whole-Earth index E(1) and its matching composite solar wind driving function S(1) are derived. A system science methodology is used based on a time-dependent magnetospheric state vector and a solar wind state vector, with canonical correlation analysis (CCA) used to reduce the two state vectors to the two time-dependent scalars E(1)(t) and S(1)(t). The whole-Earth index E(1) is based on a diversity of measures via six diverse geomagnetic indices that will be readily available in the future: SML, SMU, Ap60, SYMH, ASYM, and PCC. The CCA-derived composite index has several advantages: 1) the new “canonical” geomagnetic index E(1) will provide a more powerful description of magnetospheric activity, a description of the collective behavior of the magnetosphere–ionosphere system. 2) The new index E(1) is much more accurately predictable from upstream solar wind measurements on Earth. 3) Indications are that the new canonical geomagnetic index E(1) will be accurately predictable even when as-yet-unseen extreme solar wind conditions occur. The composite solar wind driver S(1) can also be used as a universal driver function for individual geomagnetic indices or for magnetospheric particle populations. To familiarize the use of the new index E(1), its behavior is examined in different phases of the solar cycle, in different types of solar wind plasma, during high-speed stream-driven storms, during CME sheath-driven storms, and during superstorms. It is suggested that the definition of storms are the times when E(1) >1.

Type: Article
Title: A system science methodology develops a new composite highly predictable index of magnetospheric activity for the community: the whole-Earth index E(1)
Open access status: An open access version is available from UCL Discovery
DOI: 10.3389/fspas.2023.1214804
Publisher version: https://doi.org/10.3389/fspas.2023.1214804
Language: English
Additional information: Copyright © 2023 Borovsky and Lao. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/. The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Keywords: Geomagnetic indices, geomagnetic activity, magnetosphere, solar wind, system science, canonical correlation analysis, ionosphere
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics
URI: https://discovery.ucl.ac.uk/id/eprint/10178922
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