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Association of Equatorward Extended Auroral Streamers With Overshielding Conditions at Equatorial Latitudes: First Observations.

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Title: Association of Equatorward Extended Auroral Streamers With Overshielding Conditions at Equatorial Latitudes: First Observations.
Authors: Yadav, Sneha1 (AUTHOR) snehay@atmos.ucla.edu, Lyons, Larry. R.1 (AUTHOR), Nishimura, Yukitoshi2 (AUTHOR), Weygand, James M.3 (AUTHOR), Liu, Jiang1,3 (AUTHOR), Zhang, Shun‐Rong4 (AUTHOR), Tian, Sheng1 (AUTHOR), Zou, Ying5 (AUTHOR), Donovan, Eric F.6 (AUTHOR)
Source: Journal of Geophysical Research. Space Physics. Nov2023, Vol. 128 Issue 11, p1-19. 19p.
Subject Terms: *Magnetic storms, Auroras, Equatorial electrojet, Plasma flow, Electric fields, Latitude
Abstract: We report the first observations of the association between equatorward extending streamers and overshielding using the THEMIS all‐sky imagers and ground magnetometers. Because auroral streamers indicate plasma sheet flow bursts, these observations uncover the effect of flow bursts on overshielding. Results show that, in general, bright equatorward extended streamers were associated with an increase in equatorial electrojet (EEJ) on the nightside and a decrease in the dayside EEJ, indicating a striking correspondence between auroral streamers and overshielding conditions. Thus, the driving of overshielding at equatorial latitudes can be identified via bright equatorward extended streamers, indicating that flow bursts are an alternate means to discern the earthward injections that increase the region 2 field aligned currents and associated overshielding electric fields. Repetitive auroral streamers were associated with repetitive overshielding, resulting in a stepwise development of the dayside and nightside EEJ. The stepwise intensifications were also observed in the midlatitude positive bay and Pi2 pulsations. Our results could explain the occurrence of overshielding conditions at equatorial latitudes during substorms and nonsubstorm times without a northward turning of IMF‐Bz. As seen through streamers, the localized current structures (wedgelets) associated with flow bursts giving injection that leads to overshielding is titled northeast‐to‐southwest. Our results add a new element to the understanding of high‐to‐low latitude electrodynamical coupling by demonstrating the association between bright equatorward extended auroral streamers and enhanced shielding electric fields caused by earthward injections associated with flow bursts. Key Points: The driving of overshielding seen at equatorial latitudes by injections can be identified via equatorward extending auroral streamersRepetitive streamers, thus repetitive injections, are associated with repetitive overshielding conditionsAs seen via streamers, localized current system with flow bursts giving injection driven overshielding is tilted northeast‐to‐southwest [ABSTRACT FROM AUTHOR]
Copyright of Journal of Geophysical Research. Space Physics is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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  Label: Title
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  Data: Association of Equatorward Extended Auroral Streamers With Overshielding Conditions at Equatorial Latitudes: First Observations.
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  Data: <searchLink fieldCode="AR" term="%22Yadav%2C+Sneha%22">Yadav, Sneha</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> snehay@atmos.ucla.edu</i><br /><searchLink fieldCode="AR" term="%22Lyons%2C+Larry%2E+R%2E%22">Lyons, Larry. R.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Nishimura%2C+Yukitoshi%22">Nishimura, Yukitoshi</searchLink><relatesTo>2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Weygand%2C+James+M%2E%22">Weygand, James M.</searchLink><relatesTo>3</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Liu%2C+Jiang%22">Liu, Jiang</searchLink><relatesTo>1,3</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Zhang%2C+Shun‐Rong%22">Zhang, Shun‐Rong</searchLink><relatesTo>4</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Tian%2C+Sheng%22">Tian, Sheng</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Zou%2C+Ying%22">Zou, Ying</searchLink><relatesTo>5</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Donovan%2C+Eric+F%2E%22">Donovan, Eric F.</searchLink><relatesTo>6</relatesTo> (AUTHOR)
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  Data: <searchLink fieldCode="JN" term="%22Journal+of+Geophysical+Research%2E+Space+Physics%22">Journal of Geophysical Research. Space Physics</searchLink>. Nov2023, Vol. 128 Issue 11, p1-19. 19p.
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  Data: *<searchLink fieldCode="DE" term="%22Magnetic+storms%22">Magnetic storms</searchLink><br /><searchLink fieldCode="DE" term="%22Auroras%22">Auroras</searchLink><br /><searchLink fieldCode="DE" term="%22Equatorial+electrojet%22">Equatorial electrojet</searchLink><br /><searchLink fieldCode="DE" term="%22Plasma+flow%22">Plasma flow</searchLink><br /><searchLink fieldCode="DE" term="%22Electric+fields%22">Electric fields</searchLink><br /><searchLink fieldCode="DE" term="%22Latitude%22">Latitude</searchLink>
– Name: Abstract
  Label: Abstract
  Group: Ab
  Data: We report the first observations of the association between equatorward extending streamers and overshielding using the THEMIS all‐sky imagers and ground magnetometers. Because auroral streamers indicate plasma sheet flow bursts, these observations uncover the effect of flow bursts on overshielding. Results show that, in general, bright equatorward extended streamers were associated with an increase in equatorial electrojet (EEJ) on the nightside and a decrease in the dayside EEJ, indicating a striking correspondence between auroral streamers and overshielding conditions. Thus, the driving of overshielding at equatorial latitudes can be identified via bright equatorward extended streamers, indicating that flow bursts are an alternate means to discern the earthward injections that increase the region 2 field aligned currents and associated overshielding electric fields. Repetitive auroral streamers were associated with repetitive overshielding, resulting in a stepwise development of the dayside and nightside EEJ. The stepwise intensifications were also observed in the midlatitude positive bay and Pi2 pulsations. Our results could explain the occurrence of overshielding conditions at equatorial latitudes during substorms and nonsubstorm times without a northward turning of IMF‐Bz. As seen through streamers, the localized current structures (wedgelets) associated with flow bursts giving injection that leads to overshielding is titled northeast‐to‐southwest. Our results add a new element to the understanding of high‐to‐low latitude electrodynamical coupling by demonstrating the association between bright equatorward extended auroral streamers and enhanced shielding electric fields caused by earthward injections associated with flow bursts. Key Points: The driving of overshielding seen at equatorial latitudes by injections can be identified via equatorward extending auroral streamersRepetitive streamers, thus repetitive injections, are associated with repetitive overshielding conditionsAs seen via streamers, localized current system with flow bursts giving injection driven overshielding is tilted northeast‐to‐southwest [ABSTRACT FROM AUTHOR]
– Name: AbstractSuppliedCopyright
  Label:
  Group: Ab
  Data: <i>Copyright of Journal of Geophysical Research. Space Physics is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.)
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RecordInfo BibRecord:
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      – Type: doi
        Value: 10.1029/2023JA031726
    Languages:
      – Code: eng
        Text: English
    PhysicalDescription:
      Pagination:
        PageCount: 19
        StartPage: 1
    Subjects:
      – SubjectFull: Magnetic storms
        Type: general
      – SubjectFull: Auroras
        Type: general
      – SubjectFull: Equatorial electrojet
        Type: general
      – SubjectFull: Plasma flow
        Type: general
      – SubjectFull: Electric fields
        Type: general
      – SubjectFull: Latitude
        Type: general
    Titles:
      – TitleFull: Association of Equatorward Extended Auroral Streamers With Overshielding Conditions at Equatorial Latitudes: First Observations.
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            NameFull: Lyons, Larry. R.
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            NameFull: Liu, Jiang
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              M: 11
              Text: Nov2023
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              Y: 2023
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