Issue |
A&A
Volume 631, November 2019
|
|
---|---|---|
Article Number | A144 | |
Number of page(s) | 9 | |
Section | The Sun | |
DOI | https://doi.org/10.1051/0004-6361/201936465 | |
Published online | 08 November 2019 |
Triggering of twists in solar prominence threads
1
Department of Physics, University of Aberystwyth, Aberystwyth SY23 3BZ, UK
e-mail: yot@aaber.ac.uk
2
Departament de Fisica and Institut d’Aplicacions Computacionals de Codi Comunitari (IAC 3), Universitat de les Illes Balears, Palma de Mallorca, Spain
e-mail: roberto.soler@uib.es
Received:
6
August
2019
Accepted:
3
October
2019
Context. Magnetic twists are commonly associated with solar prominences. Twists are believed to play an important role in supporting the dense plasma against gravity as well as in prominence eruptions and coronal mass ejections, which may have a severe impact on the Earth and its near environment.
Aims. We used a simple model to mimic the formation of a prominence thread by plasma condensation with the aim of investigating the possibility of triggering twists during this process.
Methods. Temporal and spatial evolution of torsional Alfvénic perturbations driven by random photospheric motions was analysed using the linearised governing equations of motion and induction.
Results. We find that small amplitude perturbations are exponentially amplified in time as they propagate along the condensing thread. Mechanisms contributing to the rapid growth are explored. The result of the amplification process is the generation of large amplitude axisymmetric twists along the thread.
Conclusions. Magnetic twists may be triggered along a prominence thread when it is permeated by a converging flow, for example, during the evaporation and condensation of plasma along the thread. This may lead to the generation of vortices in the non-linear regime.
Key words: Sun: atmosphere / Sun: filaments / prominences / magnetohydrodynamics (MHD) / waves / instabilities
© Y. Taroyan and R. Soler 2019
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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