@article{6c8348d92c4a4cc29e748f60d5ad9e58,
title = "Interhemispheric Asymmetry Due To IMF By Within the Cusp Spherical Elementary Currents",
abstract = "Observations of interhemispheric asymmetry in the cusp region due to the interplanetary magnetic field (IMF) By component have been performed for years, but those observations typically are not simultaneous in both hemispheres and represent an average picture. Simultaneous instantaneous observations in both hemispheres are rare. We have combined four sets of magnetometers in Antarctica to produce equivalent ionospheric currents and current amplitudes at 10 s resolution using the spherical elementary current systems technique. These Antarctica spherical elementary currents are roughly conjugate to the northern hemisphere spherical elementary currents derived over Greenland and North America. We examined five intervals with large interplanetary magnetic field By positive and negative and demonstrate that the equivalent current pattern in opposite hemispheres are asymmetric with respect to one another during IMF By positive with the cusp throat opening towards the dusk in the northern hemisphere and towards the dawn in the southern hemisphere. This configuration reverses for interplanetary magnetic field By negative. In one of these events we examine the rotation of the equivalent currents in real time in the northern hemisphere. We also compare these results with virtual magnetometer predictions from the Space Weather Modeling Framework. Simultaneous spherical elementary currents observations in both hemispheres are important because they allow us to observe the evolution of the cusp throat during changing solar wind and interplanetary magnetic field conditions.",
keywords = "IMF By, conjugate observations, interhemispheric asymmetry, ionospheric currents, magnetometers, spherical elementary currents",
author = "Weygand, {J. M.} and Hartinger, {M. D.} and Strangeway, {R. J.} and Welling, {D. T.} and Hyomin Kim and J{\"u}rgen Matzka and Clauer, {C. Robert}",
note = "Funding Information: J.M. Weygand would like to acknowledge NSF GEO‐NERC award number 2027190, NASA contract 80GSFC17C0018, NASA award number 80NSSC18K1220, and NASA HSR award number 80NSSC18K1227. R.J. Strangeway, D. Welling, and J.M. Weygand would like to acknowledge NASA DRIVE/UTA award number 80675. We thank the many different groups operating magnetometer arrays for providing data for this study including: We thank the AALPIP magnetometer team at mist.nianet.org for supplying Antarctica magnetometer data. The work at New Jersey Institute of Technology was supported by NASA Grant 80NSSC21K0132 and NSF Grant OPP‐1744861. The fluxgate magnetometer projects at South Pole and AGO stations are supported by NSF Grants OPP‐1643700 and PLR‐1443507, respectively, managed by the New Jersey Institute of Technology. We thank Andrew J. Gerrard for making these data available. We thank Mervyn P. Freeman for making the British Antarctic Survey magnetometer data available. We thank Brian J. Anderson, the AMPERE team, and the AMPERE Science Data Center for providing data products derived from the Iridium Communications constellation, enabled by support from the National Science Foundation. The THEMIS UCLA magnetometer network (Ground‐based Imager and Magnetometer Network for Auroral Studies) is funded through NSF Grant AGS‐1004736. The authors thank I.R. Mann, D.K. Milling and the rest of the CARISMA team for data. CARISMA is operated by the University of Alberta, funded by the Canadian Space Agency. The Canadian Magnetic Observatory Network (CANMON) is maintained and operated by the Geological Survey of Canada— http://gsc.nrcan.gc.ca/geomag . The Magnetometer Array for Cusp and Cleft Studies (MACCS) array is supported by US National Science Foundation Grant ATM‐0827903 at Augsburg University and M. J. Engebretson, D. Murr, and E.S. Steinmetz. The McMAC Project is sponsored by the Magnetospheric Physics Program of National Science Foundation through Grant AGS‐0245139 and was maintained by Dr. Peter Chi. The Falcon magnetometers were maintained by United States Air Force Academy (USAFA) and Peter Chi. We would like to thank the DTU magnetometer team. The Solar and Terrestrial Physics (STEP) magnetometer file storage is at Department of Earth and Planetary Physics, University of Tokyo and maintained by Dr. Kanji Hayashi. Finally, the United States Geological Survey (USGS) Geomagnetism Program. Funding Information: J.M. Weygand would like to acknowledge NSF GEO-NERC award number 2027190, NASA contract 80GSFC17C0018, NASA award number 80NSSC18K1220, and NASA HSR award number 80NSSC18K1227. R.J. Strangeway, D. Welling, and J.M. Weygand would like to acknowledge NASA DRIVE/UTA award number 80675. We thank the many different groups operating magnetometer arrays for providing data for this study including: We thank the AALPIP magnetometer team at mist.nianet.org for supplying Antarctica magnetometer data. The work at New Jersey Institute of Technology was supported by NASA Grant 80NSSC21K0132 and NSF Grant OPP-1744861. The fluxgate magnetometer projects at South Pole and AGO stations are supported by NSF Grants OPP-1643700 and PLR-1443507, respectively, managed by the New Jersey Institute of Technology. We thank Andrew J. Gerrard for making these data available. We thank Mervyn P. Freeman for making the British Antarctic Survey magnetometer data available. We thank Brian J. Anderson, the AMPERE team, and the AMPERE Science Data Center for providing data products derived from the Iridium Communications constellation, enabled by support from the National Science Foundation. The THEMIS UCLA magnetometer network (Ground-based Imager and Magnetometer Network for Auroral Studies) is funded through NSF Grant AGS-1004736. The authors thank I.R. Mann, D.K. Milling and the rest of the CARISMA team for data. CARISMA is operated by the University of Alberta, funded by the Canadian Space Agency. The Canadian Magnetic Observatory Network (CANMON) is maintained and operated by the Geological Survey of Canada—http://gsc.nrcan.gc.ca/geomag. The Magnetometer Array for Cusp and Cleft Studies (MACCS) array is supported by US National Science Foundation Grant ATM-0827903 at Augsburg University and M. J. Engebretson, D. Murr, and E.S. Steinmetz. The McMAC Project is sponsored by the Magnetospheric Physics Program of National Science Foundation through Grant AGS-0245139 and was maintained by Dr. Peter Chi. The Falcon magnetometers were maintained by United States Air Force Academy (USAFA) and Peter Chi. We would like to thank the DTU magnetometer team. The Solar and Terrestrial Physics (STEP) magnetometer file storage is at Department of Earth and Planetary Physics, University of Tokyo and maintained by Dr. Kanji Hayashi. Finally, the United States Geological Survey (USGS) Geomagnetism Program. Publisher Copyright: {\textcopyright} 2023. American Geophysical Union. All Rights Reserved.",
year = "2023",
month = jun,
doi = "10.1029/2023JA031430",
language = "English (US)",
volume = "128",
journal = "Journal of Geophysical Research: Space Physics",
issn = "2169-9380",
number = "6",
}