uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Kelvin-Helmholtz waves at the Earth's magnetopause: Multiscale development and associated reconnection
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
Show others and affiliations
2009 (English)In: Journal of Geophysical Research, ISSN 0148-0227, Vol. 114, no 12, A12207- p.Article in journal (Refereed) Published
Abstract [en]

We examine traversals on 20 November 2001 of the equatorial magnetopause boundary layer simultaneously at similar to 1500 magnetic local time (MLT) by the Geotail spacecraft and at similar to 1900 MLT by the Cluster spacecraft, which detected rolled-up MHD-scale vortices generated by the Kelvin-Helmholtz instability (KHI) under prolonged northward interplanetary magnetic field conditions. Our purpose is to address the excitation process of the KHI, MHD-scale and ion-scale structures of the vortices, and the formation mechanism of the low-latitude boundary layer (LLBL). The observed KH wavelength (>4 x 10(4) km) is considerably longer than predicted by the linear theory from the thickness (similar to 1000 km) of the dayside velocity shear layer. Our analyses suggest that the KHI excitation is facilitated by combined effects of the formation of the LLBL presumably through high-latitude magnetopause reconnection and compressional magnetosheath fluctuations on the dayside, and that breakup and/or coalescence of the vortices are beginning around 1900 MLT. Current layers of thickness a few times ion inertia length similar to 100 km and of magnetic shear similar to 60 degrees existed at the trailing edges of the vortices. Identified in one such current sheet were signatures of local reconnection: Alfvenic outflow jet within a bifurcated current sheet, nonzero magnetic field component normal to the sheet, and field-aligned beam of accelerated electrons. Because of its incipient nature, however, this reconnection process is unlikely to lead to the observed dusk-flank LLBL. It is thus inferred that the flank LLBL resulted from other mechanisms, namely, diffusion and/or remote reconnection unidentified by Cluster.

Place, publisher, year, edition, pages
2009. Vol. 114, no 12, A12207- p.
National Category
Physical Sciences
URN: urn:nbn:se:uu:diva-148215DOI: 10.1029/2009JA014042ISI: 000272447000001OAI: oai:DiVA.org:uu-148215DiVA: diva2:401617
Available from: 2011-03-03 Created: 2011-03-03 Last updated: 2014-11-12Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Vaivads, Andris
By organisation
Swedish Institute of Space Physics, Uppsala Division
In the same journal
Journal of Geophysical Research
Physical Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 201 hits
ReferencesLink to record
Permanent link

Direct link