Skip to content Skip to navigation
University of Warwick
  • Study
  • |
  • Research
  • |
  • Business
  • |
  • Alumni
  • |
  • News
  • |
  • About

University of Warwick
Publications service & WRAP

Highlight your research

  • WRAP
    • Home
    • Search WRAP
    • Browse by Warwick Author
    • Browse WRAP by Year
    • Browse WRAP by Subject
    • Browse WRAP by Department
    • Browse WRAP by Funder
    • Browse Theses by Department
  • Publications Service
    • Home
    • Search Publications Service
    • Browse by Warwick Author
    • Browse Publications service by Year
    • Browse Publications service by Subject
    • Browse Publications service by Department
    • Browse Publications service by Funder
  • Help & Advice
University of Warwick

The Library

  • Login
  • Admin

Nonlinear evolution of torsional Alfvén waves

Tools
- Tools
+ Tools

Vasheghani Farahani, Soheil, Nakariakov, V. M. (Valery M.), Verwichte, E. (Erwin) and Van Doorsselaere, Tom (2012) Nonlinear evolution of torsional Alfvén waves. Astronomy & Astrophysics, 544 . A127. doi:10.1051/0004-6361/201219569

Research output not available from this repository, contact author.
Official URL: http://dx.doi.org/10.1051/0004-6361/201219569

Request Changes to record.

Abstract

Aims. We study the efficiency of the energy transfer to shorter scales in the field-aligned direction – the parallel nonlinear cascade – that accompanies the propagation of torsional Alfvén waves along open magnetic fields in the solar and stellar coronae, and compare it with the same effects for the shear Alfvén wave. The evolution of the torsional Alfvén wave is caused by the back reaction of nonlinearly induced compressive perturbations on the Alfvén wave.
Methods. The evolution of upwardly propagating torsional Alfvén waves is considered in terms of the second-order thin flux-tube approximation in a straight untwisted and non-rotating magnetic flux-tube. The Cohen-Kulsrud equation for weakly nonlinear torsional waves is derived. In the model, the effect of the cubic nonlinearity on the propagation of long-wavelength axisymmetric torsional waves is compared with the similar effect that accompanies the propagation of plane linearly-polarised (shear) Alfvén waves of small amplitude.
Results. The solution to the Cohen-Kulsrud type equation for torsional waves shows that their evolution is independent of the plasma-β, which is in contrast to the shear Alfvén wave. In a finite-β plasma, the nonlinear evolution of torsional Alfvén waves is slower and the parallel nonlinear cascade is less efficient than those of shear Alfvén waves. These results have important implications for the analysis of possible heating of the plasma and its acceleration in the upper layers of solar and stellar coronae. In particular, one-dimensional models of coronal heating and wave acceleration, which use shear Alfvén waves instead of torsional Alfvén waves, over-estimate the efficiency of these processes

Item Type: Journal Article
Divisions: Faculty of Science > Physics
Journal or Publication Title: Astronomy & Astrophysics
Publisher: EDP Sciences
ISSN: 0004-6361
Official Date: 13 August 2012
Dates:
DateEvent
13 August 2012Published
24 July 2012Accepted
Volume: 544
Number of Pages: 5
Article Number: A127
DOI: 10.1051/0004-6361/201219569
Status: Peer Reviewed
Publication Status: Published

Request changes or add full text files to a record

Repository staff actions (login required)

View Item View Item
twitter

Email us: wrap@warwick.ac.uk
Contact Details
About Us