Transpolar Arcs Are Not Always Cusp‐Aligned: Evidence of HiLDA‐Aligned Arcs
Katrougkalou, Maria Chloi; Kullen, Anita; Cai, Lei; Roth, Lorenz; Zhang, Yongliang (2024-11-06)
John Wiley & Sons
06.11.2024
Katrougkalou, M. C., Kullen, A., Cai, L., Roth, L., & Zhang, Y. (2024). Transpolar arcs are not always cusp-aligned: Evidence of HiLDA-aligned arcs. Geophysical Research Letters, 51, e2024GL111246. https://doi.org/10.1029/2024GL111246
https://creativecommons.org/licenses/by-nc-nd/4.0/
© 2024. The Author(s). This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.
https://creativecommons.org/licenses/by-nc-nd/4.0/
© 2024. The Author(s). This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.
https://creativecommons.org/licenses/by-nc-nd/4.0/
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:oulu-202411126713
https://urn.fi/URN:NBN:fi:oulu-202411126713
Tiivistelmä
Abstract
Transpolar arcs (TPAs) are often cusp-aligned. Especially when multiple TPAs appear simultaneously, they join at the auroral signature of the cusp. Here we investigate the dayside connection point of TPAs using Defense Meteorological Satellite Program measurements and identify three cases where the tip of the TPA ends in a localized brightening. One is a typical cusp spot with a TPA attached. The cusp appears just poleward of the oval with a near circular shape. In the second case, multiple cusp spots are observed over a 3 MLT wide region, each connected to a TPA. In the third case, the brightening at the tip of a TPA is identified as high-latitude dayside aurora (HiLDA). Cusp aurora appears between the HiLDA and the duskside oval. Plasma flows and particle characteristics indicate a lobe origin of the HiLDA. Our results indicate a more complicated connection between TPAs and dayside aurora than previously anticipated.
Transpolar arcs (TPAs) are often cusp-aligned. Especially when multiple TPAs appear simultaneously, they join at the auroral signature of the cusp. Here we investigate the dayside connection point of TPAs using Defense Meteorological Satellite Program measurements and identify three cases where the tip of the TPA ends in a localized brightening. One is a typical cusp spot with a TPA attached. The cusp appears just poleward of the oval with a near circular shape. In the second case, multiple cusp spots are observed over a 3 MLT wide region, each connected to a TPA. In the third case, the brightening at the tip of a TPA is identified as high-latitude dayside aurora (HiLDA). Cusp aurora appears between the HiLDA and the duskside oval. Plasma flows and particle characteristics indicate a lobe origin of the HiLDA. Our results indicate a more complicated connection between TPAs and dayside aurora than previously anticipated.
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