Dayside reconnection under interplanetary magnetic field B-y-dominated conditions: The formation and movement of bending arcs
2015 (English)In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 120, no 4, 2967-2978 p.Article in journal (Refereed) Published
Based upon a survey of global auroral images collected by the Polar Ultraviolet Imager, Kullen etal. (2002) subdivided polar cap auroral arcs into a number of categories, including that of bending arcs. We are concerned with those bending arcs that appear as a bifurcation of the dayside auroral oval and which subsequently form a spur intruding into the polar cap. Once formed, the spur moves poleward and antisunward over the lifetime of the arc. We propose that dayside bending arcs are ionospheric signatures of pulses of dayside reconnection and are therefore part of a group of transient phenomena associated with flux transfer events. We observe the formation and subsequent motion of a bending arc across the polar cap during a 30 min interval on 8 January 1999, and we show that this example is consistent with the proposed model. We quantify the motion of the arc and find it to be commensurate with the convection flows observed by both ground-based radar observations and space-based particle flow measurements. In addition, precipitating particles coincident with the arc appear to occur along open field lines, lending further support to the model.
Place, publisher, year, edition, pages
2015. Vol. 120, no 4, 2967-2978 p.
bending arcs, transpolar arcs, ionosphere
IdentifiersURN: urn:nbn:se:kth:diva-172265DOI: 10.1002/2014JA020809ISI: 000354894800043ScopusID: 2-s2.0-84961315816OAI: oai:DiVA.org:kth-172265DiVA: diva2:847070
QC 201508192015-08-192015-08-142015-08-19Bibliographically approved