liu.seSearch for publications in DiVA
Change search
ReferencesLink to record
Permanent link

Direct link
Nonlinear beam generated plasma waves as a source for enhanced plasma and ion acoustic lines
University of Michigan.
University of Oslo.
University of Oslo.
Norwegian Water Resources and Energy Directorate.
Show others and affiliations
2011 (English)In: Physics of Plasmas, ISSN 1070-664X, Vol. 18, no 5, 052107- p.Article in journal (Refereed) Published
Abstract [en]

Observations by, for instance, the EISCAT Svalbard Radar (ESR) demonstrate that the symmetry of the naturally occurring ion line in the polar ionosphere can be broken by an enhanced, nonthermal, level of fluctuations (naturally enhanced ion-acoustic lines, NEIALs). It was in many cases found that the entire ion spectrum can be distorted, also with the appearance of a third line, corresponding to a propagation velocity significantly slower than the ion acoustic sound speed. It has been argued that selective decay of beam excited primary Langmuir waves can explain some phenomena similar to those observed. We consider a related model, suggesting that a primary nonlinear process can be an oscillating two-stream instability, generating a forced low frequency mode that does not obey any ion sound dispersion relation. At later times, the decay of Langmuir waves can give rise also to enhanced asymmetric ion lines. The analysis is based on numerical results, where the initial Langmuir waves are excited by a cold dilute electron beam. By this numerical approach, we can detect fine details of the physical processes, in particular, demonstrate a strong space-time intermittency of the electron waves in agreement with observations. Our code solves the full Vlasov equation for electrons and ions, with the dynamics coupled through the electrostatic field derived from Poissons equation. The analysis distinguishes the dynamics of the background and beam electrons. This distinction simplifies the analysis for the formulation of the weakly nonlinear analytical model for the oscillating two-stream instability. The results have general applications beyond their relevance for the ionospheric observations.

Place, publisher, year, edition, pages
American Institute of Physics , 2011. Vol. 18, no 5, 052107- p.
National Category
Engineering and Technology
URN: urn:nbn:se:liu:diva-69913DOI: 10.1063/1.3582084ISI: 000292209500014OAI: diva2:433206
Original Publication: L. K. S. Daldorff, H. L. Pecseli, J. K. Trulsen, M. I. Ulriksen, B. Eliasson and Lennart Stenflo, Nonlinear beam generated plasma waves as a source for enhanced plasma and ion acoustic lines, 2011, Physics of Plasmas, (18), 5, 052107. Copyright: American Institute of Physics Available from: 2011-08-09 Created: 2011-08-08 Last updated: 2011-08-12

Open Access in DiVA

fulltext(4554 kB)316 downloads
File information
File name FULLTEXT01.pdfFile size 4554 kBChecksum SHA-512
Type fulltextMimetype application/pdf

Other links

Publisher's full text

Search in DiVA

By author/editor
Stenflo, Lennart
By organisation
Theoretical Physics The Institute of Technology
In the same journal
Physics of Plasmas
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar
Total: 316 downloads
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: 24 hits
ReferencesLink to record
Permanent link

Direct link