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

Direct link
Scale size and life time of energy conversion regions observed by Cluster in the plasma sheet
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
Show others and affiliations
2009 (English)In: Annales Geophysicae, ISSN 0992-7689, E-ISSN 1432-0576, Vol. 27, no 11, 4147-4155 p.Article in journal (Refereed) Published
Abstract [en]

In this article, and in a companion paper by Hamrin et al. (2009) [Occurrence and location of concentrated load and generator regions observed by Cluster in the plasma sheet], we investigate localized energy conversion regions (ECRs) in Earth's plasma sheet. From more than 80 Cluster plasma sheet crossings (660 h data) at the altitude of about 15-20 R-E in the summer and fall of 2001, we have identified 116 Concentrated Load Regions (CLRs) and 35 Concentrated Generator Regions (CGRs). By examining variations in the power density, E.J, where E is the electric field and J is the current density obtained by Cluster, we have estimated typical values of the scale size and life time of the CLRs and the CGRs. We find that a majority of the observed ECRs are rather stationary in space, but varying in time. Assuming that the ECRs are cylindrically shaped and equal in size, we conclude that the typical scale size of the ECRs is 2 R-E less than or similar to Delta 1 S-ECR less than or similar to 5 R-E. The ECRs hence occupy a significant portion of the mid altitude plasma sheet. Moreover, the CLRs appear to be somewhat larger than the CGRs. The life time of the ECRs are of the order of 1-10 min, consistent with the large scale magnetotail MHD simulations of Birn and Hesse (2005). The life time of the CGRs is somewhat shorter than for the CLRs. On time scales of 1-10 min, we believe that ECRs rise and vanish in significant regions of the plasma sheet, possibly oscillating between load and generator character. It is probable that at least some of the observed ECRs oscillate energy back and forth in the plasma sheet instead of channeling it to the ionosphere.

Place, publisher, year, edition, pages
2009. Vol. 27, no 11, 4147-4155 p.
Keyword [en]
Magnetospheric physics, Auroral phenomena, Magnetosphere-ionosphere interactions, Plasma sheet
National Category
Physical Sciences
URN: urn:nbn:se:uu:diva-148219DOI: 10.5194/angeo-27-4147-2009ISI: 000272232100005OAI: oai:DiVA.org:uu-148219DiVA: diva2:401605
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
Annales Geophysicae
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: 163 hits
ReferencesLink to record
Permanent link

Direct link