University of Oulu

Reistad JP, Holappa L, Ohma A, Gabrielse C, Sur D, Asikainen T and DeJong A (2022) Dependence of the global dayside reconnection rate on interplanetary magnetic field By and the earth’s dipole tilt. Front. Astron. Space Sci. 9:973276. doi: 10.3389/fspas.2022.973276

Dependence of the global dayside reconnection rate on interplanetary magnetic field By and the earth’s dipole tilt

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Author: Reistad, Jone Peter1; Holappa, Lauri2; Ohma, Anders1;
Organizations: 1Birkeland Centre for Space Science, University of Bergen, Bergen, Norway
2Space Physics and Astronomy Research Unit, University of Oulu, Oulu, Finland
3The Aerospace Corporation, El Segundo, CA, United States
4CIRES, University of Colorado Boulder, Boulder, CO, United States
5Narula Institute of Technology, Kolkata, India
6Howard Community College, Columbia, MD, United States
7NASA Goddard Space Flight Center, Greenbelt, MD, United States
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.6 MB)
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Language: English
Published: Frontiers Media, 2022
Publish Date: 2023-05-31


In the recent years, significant attention has been given to the combined effect of Interplanetary Magnetic Field (IMF) duskward component (By) and dipole tilt on the global magnetosphere-ionosphere system response. Numerous studies have pointed out that when the Earth’s magnetic dipole is tilted away from the Sun (negative dipole tilt during northern winter), and IMF has a positive By component, the effects on ionospheric currents, particle precipitation, ionospheric convection, and average size of the auroral oval, is significantly more enhanced, compared to when IMF By is negative. Furthermore, this IMF By polarity effect reverses when Earth’s dipole is tilted in the opposite direction. The underlying cause has remained unclear. Our analysis shows that substorms tend to be stronger during the same IMF By and dipole tilt polarity combination. Taken together with earlier results showing also more frequent substorms during the same conditions, our observations suggests that when IMF By and dipole tilt have opposite signs, there is a more efficient global dayside reconnection rate. We also show analysis of the occurrence frequency of periods of Steady Magnetospheric Convection, substorm onset latitude, and the isotropic boundary of proton precipitation, that are all consistent with our conclusion that the combination of IMF By and dipole tilt polarity affect the global dayside reconnection rate.

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Series: Frontiers in astronomy and space sciences
ISSN: 2296-987X
ISSN-E: 2296-987X
ISSN-L: 2296-987X
Volume: 9
Article number: 973276
DOI: 10.3389/fspas.2022.973276
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Funding: JR were funded by the Norwegian Research Council (NRC) through grant 300844/F50. LH was funded by the Academy of Finland postdoctoral project 322459. AO were funded by the Norwegian Research Council (NRC) through grant 223252/F50. DS was supported by NASA LWS 80NSSC17K0718. TA was supported by the Academy of Finland (PROSPECT project 24303278). This work was also supported by the Center for the Unified Study of Interhemispheric Asymmetries (CUSIA), NASA Award 80NSSC20K0606.
Academy of Finland Grant Number: 322459
Detailed Information: 322459 (Academy of Finland Funding decision)
Copyright information: © 2022 Reistad, Holappa, Ohma, Gabrielse, Sur, Asikainen and DeJong. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). 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.