Auroral Poleward Boundary Intensifications and Modes of Energy Transport in the Plasma Sheet
Notice bibliographique
Résumé
Auroral poleward boundary intensifications (PBIs) have an auroral signature in ground meridional scanning photometer (MSP) data that appears as an increase in intensity at or near the magnetic separatrix. This increase is often seen to extend equatorward through the ionospheric mapping of the plasma sheet. PBIs are also associated with fast flows in the tail plasma sheet and are thus an important disturbance of the auroral zone and plasma sheet. We have recently used simultaneous auroral observations from the CANOPUS MSPs and either the Freja UV imager or the CANOPUS Gillam all-sky imager (ASI) to investigate the two-dimensional structure of auroral intensifications near the poleward boundary of the oval. We found that equatorward extending PBIs are either north-south (NS) aligned structures or east-west (EW) arcs that mostly propagate equatorward, but we have not been able to determine without doubt which type is the most prevalent. The different two-dimensional orientations for equatorward extending PBIs suggests that they may be the auroral footprint of two major modes of energy transfer in the plasma sheet: multiple, narrow, earthward fast-flow channels (associated with the NS structures) and sequences of azimuthally broad and primarily earthward propagating phase fronts initiating near the separatrix (associated with the EW arcs). We test this hypothesis by combining data from the CANOPUS MSPs, the all-sky imagers of the newly installed NORSTAR array in northern Canada which cover the poleward boundary of the auroral oval, auroral images from the IMAGE spacecraft, and magnetic field and plasma data from the Geotail spacecraft. We discuss, in particular, two events. First, an event from Jan 3, 2001 when multiple PBIs occurred during the long recovery phase of a substorm. We find that PBIs correlate well with plasma sheet fast flows that occur within the local time sector of PBIs. Most of the PBIs are EW arcs that initiate near the poleward boundary and then propagate equatorward. They often tilt and become approximately NS structures as they propagate equatorward. Second, an event from Jan 13, 2001 that occurs during very quiet (northward IMF) conditions and is not associated with a substorm. The PBIs are EW arcs and the ionospheric footprint of a triple flow burst in the plasma sheet. These two events suggest that, contrary to our previous suggestion, the same dynamics likely produce both EW and NS structures and that similar plasma sheet dynamics may occur both during the recovery phase of a substorm under southward IMF and during a
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Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».