Numerical simulations of conversion to Alfven waves in solar active regions

Elena Khomenko, Paul Stuart Cally

Research output: Chapter in Book/Report/Conference proceedingConference PaperResearchpeer-review

22 Citations (Scopus)

Abstract

We study the coupling of magneto-acoustic waves to Alven waves using 2.5D numerical simulations. In our experiment, a fast magnetoacoustic wave of a given frequency and wavenumber is generated below the surface. The magnetic field in the domain is assumed homogeneous and inclined. The efficiency of the conversion to Alfven waves near the layer of equal acoustic and Alfven speeds is measured calculating their energy flux. The particular amplitude and phase relations between the oscillations of magnetic field and velocity help us to demonstrate that the waves produced after the transformation and reaching upper atmosphere are indeed Alfven waves. We find that the conversion from fast magneto-acoustic waves to Alfven waves is particularly important for the inclination theta and azimuth phi angles of the magnetic field between 55 and 65 degrees, with the maximum shifted to larger inclinations for lower frequency waves. The maximum Alfven flux transmitted to the upper atmosphere is about 2-3 times lower than the corresponding acoustic flux.
Original languageEnglish
Title of host publicationJournal of Physics: Conference Series [P]
EditorsThierry Appourchaux
Place of PublicationUK
PublisherIOP Publishing
Pages1 - 4
Number of pages4
Volume271
ISBN (Print)1742-6588
DOIs
Publication statusPublished - 2011
EventJoint Conference of the Global Oscillation Network Group and Solar and Heliospheric Observatory (GONG/SOHO) 2011 - Aix-en-Provence, France
Duration: 27 Jun 20102 Jul 2010

Conference

ConferenceJoint Conference of the Global Oscillation Network Group and Solar and Heliospheric Observatory (GONG/SOHO) 2011
Abbreviated titleGONG2010–SoHO24
CountryFrance
CityAix-en-Provence
Period27/06/102/07/10
OtherVolume 271 (2011) of the Journal of Physics: Conference Series provides a record of the invited and contributed talks, and of the posters presented at the GONG2010–SoHO24 conference entitled 'A new era of seismology of the Sun and solar-like stars'. The conference was held from 27 June 2010 to 2 July 2010 in Aix-en-Provence, France.

Cite this

Khomenko, E., & Cally, P. S. (2011). Numerical simulations of conversion to Alfven waves in solar active regions. In T. Appourchaux (Ed.), Journal of Physics: Conference Series [P] (Vol. 271, pp. 1 - 4). UK: IOP Publishing. https://doi.org/10.1088/1742-6596/271/1/012042
Khomenko, Elena ; Cally, Paul Stuart. / Numerical simulations of conversion to Alfven waves in solar active regions. Journal of Physics: Conference Series [P]. editor / Thierry Appourchaux. Vol. 271 UK : IOP Publishing, 2011. pp. 1 - 4
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Khomenko, E & Cally, PS 2011, Numerical simulations of conversion to Alfven waves in solar active regions. in T Appourchaux (ed.), Journal of Physics: Conference Series [P]. vol. 271, IOP Publishing, UK, pp. 1 - 4, Joint Conference of the Global Oscillation Network Group and Solar and Heliospheric Observatory (GONG/SOHO) 2011, Aix-en-Provence, France, 27/06/10. https://doi.org/10.1088/1742-6596/271/1/012042

Numerical simulations of conversion to Alfven waves in solar active regions. / Khomenko, Elena; Cally, Paul Stuart.

Journal of Physics: Conference Series [P]. ed. / Thierry Appourchaux. Vol. 271 UK : IOP Publishing, 2011. p. 1 - 4.

Research output: Chapter in Book/Report/Conference proceedingConference PaperResearchpeer-review

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AB - We study the coupling of magneto-acoustic waves to Alven waves using 2.5D numerical simulations. In our experiment, a fast magnetoacoustic wave of a given frequency and wavenumber is generated below the surface. The magnetic field in the domain is assumed homogeneous and inclined. The efficiency of the conversion to Alfven waves near the layer of equal acoustic and Alfven speeds is measured calculating their energy flux. The particular amplitude and phase relations between the oscillations of magnetic field and velocity help us to demonstrate that the waves produced after the transformation and reaching upper atmosphere are indeed Alfven waves. We find that the conversion from fast magneto-acoustic waves to Alfven waves is particularly important for the inclination theta and azimuth phi angles of the magnetic field between 55 and 65 degrees, with the maximum shifted to larger inclinations for lower frequency waves. The maximum Alfven flux transmitted to the upper atmosphere is about 2-3 times lower than the corresponding acoustic flux.

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Khomenko E, Cally PS. Numerical simulations of conversion to Alfven waves in solar active regions. In Appourchaux T, editor, Journal of Physics: Conference Series [P]. Vol. 271. UK: IOP Publishing. 2011. p. 1 - 4 https://doi.org/10.1088/1742-6596/271/1/012042