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Separation and Quantification of Ionospheric Convection Sources: 2. The Dipole Tilt Angle Influence on Reverse Convection Cells During Northward IMF

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posted on 07.08.2019, 15:01 by JP Reistad, KM Laundal, N Østgaard, A Ohma, EG Thomas, S Haaland, K Oksavik, SE Milan
This paper investigates the influence of Earth's dipole tilt angle on the reverse convection cells (sometimes referred to as lobe cells) in the Northern Hemisphere ionosphere during northward IMF, which we relate to high-latitude reconnection. Super Dual Auroral Radar Network plasma drift observations in 2010–2016 are used to quantify the ionospheric convection. A novel technique based on Spherical Elementary Convection Systems (SECS) that was presented in our companion paper (Reistad et al., 2019, https://doi.org/10.1029/2019JA026634) is used to isolate and quantify the reverse convection cells. We find that the dipole tilt angle has a linear influence on the reverse cell potential. In the Northern Hemisphere the reverse cell potential is typically two times higher in summer than in winter. This change is interpreted as the change in interplanetary magnetic field-lobe reconnection rate due to the orientation of the dipole tilt. Hence, the dipole tilt influence on reverse ionospheric convection can be a significant modification of the more known influence from vswBz. These results could be adopted by the scientific community as key input parameters for lobe reconnection coupling functions.

Funding

SuperDARN (Super Dual Auroral Radar Network) is an international collaboration involving more than 30 low‐power HF radars that are operated and funded by universities and research organizations in Australia, Canada, China, France, Italy, Japan, Norway, South Africa, the United Kingdom, and the United States. The SuperDARN data were obtained directly from Evan Thomas, but raw files can be accessed via the SuperDARN data mirrors hosted by the British Antarctic Survey (https://www.bas.ac.uk/project/superdarn/#data) and University of Saskatchewan (https://superdarn.ca). We acknowledge the use of NASA/GSFC's Space Physics Data fFacility (http://omniweb.gsfc.nasa.gov) for OMNI data. Financial support has also been provided to the authors by the Research Council of Norway under the contract 223252.

History

Citation

Journal of Geophysical Research: Space Physics, 2019, 124

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy

Version

VoR (Version of Record)

Published in

Journal of Geophysical Research: Space Physics

Publisher

American Geophysical Union (AGU), Wiley

issn

2169-9380

eissn

2169-9402

Acceptance date

08/06/2019

Copyright date

2019

Available date

07/08/2019

Publisher version

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019JA026641

Notes

This article is a companion to Reistad et al. (2019), https://doi.org/10.1029/2019JA026634. http://hdl.handle.net/2381/45136

Language

en

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