High-latitude electrodynamics and aurorae during northward IMF
1993 (English)In: Auroral Plasma Dynamics, Washington, DC: American Geophysical Union (AGU), 1993, 55-68 p.Chapter in book (Refereed)
The large-scale auroral morphology and its associated electrodynamics for northward interplanetary magnetic field (IMF) is characteristically different from that for southward IMF. For northward IMF significant auroral activity is often present poleward of the “normal” auroral oval, and a number of different polar auroral configurations can occur. Two extreme situations which are considered here are either one where one or more discrete arcs separated from the “normal” oval are present in the polar region, or one where diffuse auroral activity is found in a large fraction of this region. The latter case might be associated with so-called NBZ (field-aligned) currents. We briefly review the typical signatures in terms of optical emissions, field-aligned currents, electric fields, and plasma convection usually encountered in the polar region when IMF Bz<0, and their interrelationships. This is the starting point for a more detailed discussion, driven by modeling results, of the relationships between electric field, field-aligned current, and conductivity in the two distinct situations mentioned. In particular we discuss the influence the polar field-aligned currents have on the convection pattern, on the small as well as on the large scale. As expected, currents associated with discrete isolated arcs give rise mainly to small-scale modifications, whereas currents related to auroral activity in an expanded oval can modify the overall convection pattern substantially.
Place, publisher, year, edition, pages
Washington, DC: American Geophysical Union (AGU), 1993. 55-68 p.
, Geophys. Monogr. Ser.
2431 Ionosphere: Ionosphere-magnetosphere interactions, 2475 Ionosphere: Polar ionosphere, Auroras, Space plasmas—Plasma dynamics
Fusion, Plasma and Space Physics
IdentifiersURN: urn:nbn:se:kth:diva-92039OAI: oai:DiVA.org:kth-92039DiVA: diva2:511951
NR 201408052012-03-252012-03-252012-03-25Bibliographically approved