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Park, J.-S., Shi, Q. Q., Nowada, M., Shue, J.-H., Kim, K.-H., Lee, D.-H., et al. (2021). Transpolar arcs during a prolonged radial interplanetary magnetic field interval. Journal of Geophysical Research: Space Physics, 126, e2021JA029197.

Transpolar arcs during a prolonged radial interplanetary magnetic field interval

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Author: Park, Jong-Sun1; Shi, Quan Qi1; Nowada, Motoharu1;
Organizations: 1Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, Institute of Space Sciences, Shandong University, Weihai, China
2Institute of Space Science, National Central University, Taoyuan, Taiwan
3School of Space Research, Kyung Hee University, Gyeonggi, South Korea
4Institute of Space Physics and Applied Technology, Peking University, Beijing, China
5Department of Physics, Umeå University, Umeå, Sweden
6Space Physics and Astronomy Research Unit, University of Oulu, Oulu, Finland
7The Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
8Department of Space and Climate Physics, Mullard Space Science Laboratory, University College London, Dorking, UK
9William B. Hanson Center for Space Sciences, University of Texas at Dallas, Richardson, TX, USA
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 4.3 MB)
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Language: English
Published: American Geophysical Union, 2021
Publish Date: 2021-11-28


Transpolar arcs (TPAs) are believed to predominantly occur under northward interplanetary magnetic field (IMF) conditions with their hemispheric asymmetry controlled by the Sun-Earth (radial) component of the IMF. In this study, we present observations of TPAs that appear in both the northern and southern hemispheres even during a prolonged interval of radially oriented IMF. The Defense Meteorological Satellite Program (DMSP) F16 and the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellites observed TPAs on the dawnside polar cap in both hemispheres (one TPA structure in the southern hemisphere and two in the northern hemisphere) during an interval of nearly earthward-oriented IMF on October 29, 2005. The southern hemisphere TPA and one of the northern hemisphere TPAs are associated with electron and ion precipitation and mostly sunward plasma flow (with shears) relative to their surroundings. Meanwhile, the other TPA in the northern hemisphere is associated with an electron-only precipitation and antisunward flow relative to its surroundings. Our observations indicate the following: (a) the TPA formation is not limited to northward IMF conditions; (b) the TPAs can be located on both closed field lines rooted in the polar cap of both hemispheres and open field lines connected to the northward field lines draped over one hemisphere of the magnetopause. We believe that the TPAs presented here are the result of both indirect and direct processes of solar wind energy transfer to the high-latitude ionosphere.

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Series: Journal of geophysical research. Space physics
ISSN: 2169-9380
ISSN-E: 2169-9402
ISSN-L: 2169-9380
Volume: 126
Issue: 6
Article number: e2021JA029197
DOI: 10.1029/2021JA029197
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Funding: This work was supported by NSFC grant 41850410495. Q. Q. Shi is supported by NSFC grants 41974189 and 41961130382 and the Royal Society NAF/R1/191047. M. Nowada is supported by NSFC grant 42074194. The work of K.-H. Kim was supported by the Basic Science Research Program through NRF funded by NRF-2019R1F1A1055444. A. M. Tian is supported by the Shandong University (Weihai) Future Plan for Young Scholars (2017WHWLJH08). T. Pitkänen was supported by NSFC grant 41750110486 and SNSA grant 118/17. I. J. Rae is supported in part by STFC grants ST/N0007722/1 and ST/S000240/1 and NERC grants NE/P017150/1 and NE/P017185/1.
Dataset Reference: DMSP F16/SSUSI data were obtained from TIMED/GUVI data are available at DMSP/SSJ data were obtained from DMSP/SSIES and DMSP/SSM data are accessible from the Madrigal database ( The coefficients and software used to transform the DMSP satellite position from geographic (obtained from into AACGM coordinates are downloadable at OMNI data were obtained from The software used to obtain the Earth's dipole tilt angle is downloadable at AL and AU indices were obtained from
Copyright information: © 2021. American Geophysical Union.