World Library  


Add to Book Shelf
Flag as Inappropriate
Email this Book

Characteristics of Quasi-static Potential Structures Observed in the Auroral Return Current Region by Cluster : Volume 11, Issue 5/6 (21/12/2004)

By Marklund, G. T.

Click here to view

Book Id: WPLBN0004019648
Format Type: PDF Article :
File Size: Pages 12
Reproduction Date: 2015

Title: Characteristics of Quasi-static Potential Structures Observed in the Auroral Return Current Region by Cluster : Volume 11, Issue 5/6 (21/12/2004)  
Author: Marklund, G. T.
Volume: Vol. 11, Issue 5/6
Language: English
Subject: Science, Nonlinear, Processes
Collections: Periodicals: Journal and Magazine Collection (Contemporary), Copernicus GmbH
Historic
Publication Date:
2004
Publisher: Copernicus Gmbh, Göttingen, Germany
Member Page: Copernicus Publications

Citation

APA MLA Chicago

Johansson, T., André, M., Buchert, S., Kistler, L. M., Lindqvist, P., Fazakerley, A.,...Figueiredo, S. (2004). Characteristics of Quasi-static Potential Structures Observed in the Auroral Return Current Region by Cluster : Volume 11, Issue 5/6 (21/12/2004). Retrieved from http://hawaiilibrary.net/


Description
Description: Division of Plasma Physics, Alfvén Laboratory, Royal Institute of Technology, SE 10044 Stockholm, Sweden. Temporal and spatial characteristics of intense quasi-static electric fields and associated electric potential structures in the return current region are discussed using Cluster observations at geocentric distances of about 5 Earth radii. Results are presented from four Cluster encounters with such acceleration structures to illustrate common as well as different features of such structures. The electric field structures are characterized by (all values are projected to 100 km altitude) peak amplitudes of ≈1V/m, bipolar or unipolar profiles, perpendicular scale sizes of ≈10km, occurrence at auroral plasma boundaries associated with plasma density gradients, downward field-aligned currents of ≈10µA/m2, and upward electron beams with characteristic energies of a few hundred eV to a fewkeV. Two events illustrate the temporal evolution of bipolar, diverging electric field structures, indicative of positive U-shaped potentials increasing in magnitude from less than 1kV to a few kV on a few 100s time scale. This is also the typical formation time for ionospheric plasma cavities, which are connected to the potential structure and suggested to evolve hand-in-hand with these. In one of these events an energy decay of inverted-V ions was observed in the upward field-aligned current region prior to the acceleration potential increase in the adjacent downward current region, possibly suggesting that a potential redistribution took place between the two current branches. The other two events were characterized by intense unipolar electric fields, indicative of S-shaped potential contours and were encountered at the polar cap boundary. The total observation time for these events was typically 10-20s, too short for monitoring the evolution of the structure, but yet of interest for revealing their short term stability. The locations of the two bipolar events at the poleward boundary of the central plasma sheet and of the two unipolar events at the polar cap boundary, suggest that the special profile shape depends on whether plasma populations, dense enough to support upward field-aligned currents and closure of the return current, exist on both sides, or on one side only, of the boundary.

Summary
Characteristics of quasi-static potential structures observed in the auroral return current region by Cluster

 

Click To View

Additional Books


  • Spectral Evolution of Two-layer Weak Geo... (by )
  • Spectral Properties of Electromagnetic T... (by )
  • Rossby-wave Turbulence in a Rapidly Rota... (by )
  • Reconnection Current Sheet Structure in ... (by )
  • Plankton Bloom Controlled by Horizontal ... (by )
  • Brief Communication: the Double Layer in... (by )
  • Elastic Envelope Inversion Using Multico... (by )
  • Flash-flood Forecasting by Means of Neur... (by )
  • Nonlinear Multivariable Analysis of Soi ... (by )
  • Large-scale Instability of a Generalized... (by )
  • Preface Nonlinear Processes in Oceanic a... (by )
  • Quantitative Analysis of Randomness Exhi... (by )
Scroll Left
Scroll Right

 



Copyright © World Library Foundation. All rights reserved. eBooks from Hawaii eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.