How to turn gravity waves into Alfven waves and other such tricks

Marie Newington, Paul Stuart Cally

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

2 Citations (Scopus)

Abstract

Recent observations of travelling gravity waves at the base of the chromosphere suggest an interplay between gravity wave propagation and magnetic field. Our aims are: to explain the observation that gravity wave flux is suppressed in magnetic regions; to understand why we see travelling waves instead of standing waves; and to see if gravity waves can undergo mode conversion and couple to Alfven waves in regions where the plasma beta is of order unity. We model gravity waves in a VAL C atmosphere, subject to a uniform magnetic field of various orientations, considering both adiabatic and radiatively damped propagation. Results indicate that in the presence of a magnetic field, the gravity wave can propagate as a travelling wave, with the magnetic field orientation playing a crucial role in determining the wave character. For the majority of magnetic field orientations, the gravity wave is reflected at low heights as a slow magneto-acoustic wave, explaining the observation of reduced flux in magnetic regions. In a highly inclined magnetic field, the gravity wave undergoes mode conversion to either field guided acoustic waves or Alfven waves. The primary effect of incorporating radiative damping is a reduction in acoustic and magnetic fluxes measured at the top of the integration region. By demonstrating the mode conversion of gravity waves to Alfven waves, this work identifies a possible pathway for energy transport from the solar surface to the upper atmosphere.
Original languageEnglish
Title of host publicationJournal of Physics: Conference Series [P]
EditorsThierry Appourchaux
Place of PublicationBristol UK
PublisherInstitute of Physics Publishing (IOP 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

Newington, M., & Cally, P. S. (2011). How to turn gravity waves into Alfven waves and other such tricks. In T. Appourchaux (Ed.), Journal of Physics: Conference Series [P] (Vol. 271, pp. 1 - 4). Bristol UK: Institute of Physics Publishing (IOP Publishing). https://doi.org/10.1088/1742-6596/271/1/012037
Newington, Marie ; Cally, Paul Stuart. / How to turn gravity waves into Alfven waves and other such tricks. Journal of Physics: Conference Series [P]. editor / Thierry Appourchaux. Vol. 271 Bristol UK : Institute of Physics Publishing (IOP Publishing), 2011. pp. 1 - 4
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abstract = "Recent observations of travelling gravity waves at the base of the chromosphere suggest an interplay between gravity wave propagation and magnetic field. Our aims are: to explain the observation that gravity wave flux is suppressed in magnetic regions; to understand why we see travelling waves instead of standing waves; and to see if gravity waves can undergo mode conversion and couple to Alfven waves in regions where the plasma beta is of order unity. We model gravity waves in a VAL C atmosphere, subject to a uniform magnetic field of various orientations, considering both adiabatic and radiatively damped propagation. Results indicate that in the presence of a magnetic field, the gravity wave can propagate as a travelling wave, with the magnetic field orientation playing a crucial role in determining the wave character. For the majority of magnetic field orientations, the gravity wave is reflected at low heights as a slow magneto-acoustic wave, explaining the observation of reduced flux in magnetic regions. In a highly inclined magnetic field, the gravity wave undergoes mode conversion to either field guided acoustic waves or Alfven waves. The primary effect of incorporating radiative damping is a reduction in acoustic and magnetic fluxes measured at the top of the integration region. By demonstrating the mode conversion of gravity waves to Alfven waves, this work identifies a possible pathway for energy transport from the solar surface to the upper atmosphere.",
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Newington, M & Cally, PS 2011, How to turn gravity waves into Alfven waves and other such tricks. in T Appourchaux (ed.), Journal of Physics: Conference Series [P]. vol. 271, Institute of Physics Publishing (IOP Publishing), Bristol 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/10.1088/1742-6596/271/1/012037

How to turn gravity waves into Alfven waves and other such tricks. / Newington, Marie; Cally, Paul Stuart.

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

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

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AB - Recent observations of travelling gravity waves at the base of the chromosphere suggest an interplay between gravity wave propagation and magnetic field. Our aims are: to explain the observation that gravity wave flux is suppressed in magnetic regions; to understand why we see travelling waves instead of standing waves; and to see if gravity waves can undergo mode conversion and couple to Alfven waves in regions where the plasma beta is of order unity. We model gravity waves in a VAL C atmosphere, subject to a uniform magnetic field of various orientations, considering both adiabatic and radiatively damped propagation. Results indicate that in the presence of a magnetic field, the gravity wave can propagate as a travelling wave, with the magnetic field orientation playing a crucial role in determining the wave character. For the majority of magnetic field orientations, the gravity wave is reflected at low heights as a slow magneto-acoustic wave, explaining the observation of reduced flux in magnetic regions. In a highly inclined magnetic field, the gravity wave undergoes mode conversion to either field guided acoustic waves or Alfven waves. The primary effect of incorporating radiative damping is a reduction in acoustic and magnetic fluxes measured at the top of the integration region. By demonstrating the mode conversion of gravity waves to Alfven waves, this work identifies a possible pathway for energy transport from the solar surface to the upper atmosphere.

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Newington M, Cally PS. How to turn gravity waves into Alfven waves and other such tricks. In Appourchaux T, editor, Journal of Physics: Conference Series [P]. Vol. 271. Bristol UK: Institute of Physics Publishing (IOP Publishing). 2011. p. 1 - 4 https://doi.org/10.1088/1742-6596/271/1/012037