Dayside aurorae and polar arcs under south-east IMF orientation
Abstract. We document a characteristic spatial and temporal structure of the aurora in the postnoon sector present during a 10-h-long interval of very steady southeast IMF orientation (clock angle=135 ◦ ) ending in a sharp south-to-north transition. Focus is placed on the detailed morphology of auro...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.404.6947 2023-05-15T16:29:42+02:00 Dayside aurorae and polar arcs under south-east IMF orientation M. Dyrl C. J. Farrugia The Pennsylvania State University CiteSeerX Archives application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.404.6947 http://hal.archives-ouvertes.fr/docs/00/31/82/40/PDF/angeo-24-3421-2006.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.404.6947 http://hal.archives-ouvertes.fr/docs/00/31/82/40/PDF/angeo-24-3421-2006.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://hal.archives-ouvertes.fr/docs/00/31/82/40/PDF/angeo-24-3421-2006.pdf text ftciteseerx 2016-01-08T02:59:34Z Abstract. We document a characteristic spatial and temporal structure of the aurora in the postnoon sector present during a 10-h-long interval of very steady southeast IMF orientation (clock angle=135 ◦ ) ending in a sharp south-to-north transition. Focus is placed on the detailed morphology of auroral forms/activities corresponding to merging and lobe convection cells obtained from SuperDARN convection data and Greenland magnetograms. The ground optical instruments at Ny ˚Alesund, Svalbard (76 ◦ MLAT) recorded different auroral forms/activities as the station moved to higher magnetic local times (MLTs) in the 13:00–17:00 MLT sector. Whereas the 13:00–15:00 MLT sector is characterized by classical poleward moving auroral forms (PMAFs) associated with merging cell transients, the aurora in the 15:00– 17:00 MLT sector shows instead a characteristic latitudinal bifurcation consisting of standard oval forms and polar arcs, and a corresponding composite pattern of merging and lobe convection cells. The merging and lobe cells respond to the southward and northward IMF transitions by activation/fading and fading/activation, respectively. A sequence of brightening events is characterized by successive activations progressing in latitude from the merging cell regime to the lobe cell regime. Emphasis is placed on the association between polar arc brightenings and the activation of the channel of enhanced sunward flow in the lobe cell. The observations are discussed in relation to recent work on solar wind-magnetosphere-ionosphere interconnection topology. Text Greenland Svalbard Unknown Greenland Svalbard |
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description |
Abstract. We document a characteristic spatial and temporal structure of the aurora in the postnoon sector present during a 10-h-long interval of very steady southeast IMF orientation (clock angle=135 ◦ ) ending in a sharp south-to-north transition. Focus is placed on the detailed morphology of auroral forms/activities corresponding to merging and lobe convection cells obtained from SuperDARN convection data and Greenland magnetograms. The ground optical instruments at Ny ˚Alesund, Svalbard (76 ◦ MLAT) recorded different auroral forms/activities as the station moved to higher magnetic local times (MLTs) in the 13:00–17:00 MLT sector. Whereas the 13:00–15:00 MLT sector is characterized by classical poleward moving auroral forms (PMAFs) associated with merging cell transients, the aurora in the 15:00– 17:00 MLT sector shows instead a characteristic latitudinal bifurcation consisting of standard oval forms and polar arcs, and a corresponding composite pattern of merging and lobe convection cells. The merging and lobe cells respond to the southward and northward IMF transitions by activation/fading and fading/activation, respectively. A sequence of brightening events is characterized by successive activations progressing in latitude from the merging cell regime to the lobe cell regime. Emphasis is placed on the association between polar arc brightenings and the activation of the channel of enhanced sunward flow in the lobe cell. The observations are discussed in relation to recent work on solar wind-magnetosphere-ionosphere interconnection topology. |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
M. Dyrl C. J. Farrugia |
spellingShingle |
M. Dyrl C. J. Farrugia Dayside aurorae and polar arcs under south-east IMF orientation |
author_facet |
M. Dyrl C. J. Farrugia |
author_sort |
M. Dyrl |
title |
Dayside aurorae and polar arcs under south-east IMF orientation |
title_short |
Dayside aurorae and polar arcs under south-east IMF orientation |
title_full |
Dayside aurorae and polar arcs under south-east IMF orientation |
title_fullStr |
Dayside aurorae and polar arcs under south-east IMF orientation |
title_full_unstemmed |
Dayside aurorae and polar arcs under south-east IMF orientation |
title_sort |
dayside aurorae and polar arcs under south-east imf orientation |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.404.6947 http://hal.archives-ouvertes.fr/docs/00/31/82/40/PDF/angeo-24-3421-2006.pdf |
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Greenland Svalbard |
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Greenland Svalbard |
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Greenland Svalbard |
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Greenland Svalbard |
op_source |
http://hal.archives-ouvertes.fr/docs/00/31/82/40/PDF/angeo-24-3421-2006.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.404.6947 http://hal.archives-ouvertes.fr/docs/00/31/82/40/PDF/angeo-24-3421-2006.pdf |
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Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
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1766019410255937536 |