 |
| Titel |
Polar cap convection events and electrojet intensifications in substorms/pseudobreakups |
| VerfasserIn |
Yngvild Andalsvik, Per Even Sandholt, Charlie Farrugia |
| Konferenz |
EGU General Assembly 2011
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250048579
|
|
|
|
|
|
| Zusammenfassung |
| We report an investigation of the association between polar cap convection events and
electrojet intensifications in substorms/pseudobreakups. The data basis consists of three cases
of ground- and satellite observations in the 1500-2000 MLT sector. We take advantage of the
good latitudinal coverage in the polar cap and in the auroral zone of the IMAGE chain
of ground magnetometers in Svalbard - Scandinavia - Russia. Two of the events
were obtained during strong solar wind forcing of the magnetosphere at the time
of the Earth passage of interplanetary CMEs. In all three cases we focus on the
temporal evolution of polar cap convection in relation to electrojet intensifications in
substorms/pseudobreakups. Based on these and previous observations we suggest an
evolution of the magnetosphere-ionosphere system initiated by transient magnetopause
reconnection which includes the following elements: plasma flow enhancements
on open field lines in two consecutive stages (dayside and polar cap), followed
by plasma sheet thinning, current sheet disruption, bursty bulk flows (BBFs) and
poleward boundary intensification (PBI) in the nightside aurora, accompanied by
intensification of the westward electrojet (WEJ). In this study we emphasize the role of
10-min-long events of enhanced momentum transfer to the polar cap ionosphere in the
stage of old open field lines as a precursor activity for electrojet intensifications in
substorms/pseudobreakups. |
|
|
|
|
|
|