Magnetoacoustic wave energy dissipation in the atmosphere of solar pores

Caitlin A. Gilchrist-Millar*, David B. Jess, Samuel D.T. Grant, Peter H. Keys, Christian Beck, Shahin Jafarzadeh, Julia M. Riedl, Tom Van Doorsselaere, Basilio Ruiz Cobo

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

The suitability of solar pores as magnetic wave guides has been a key topic of discussion in recent years. Here, we present observational evidence of propagating magnetohydrodynamic wave activity in a group of five photospheric solar pores. Employing data obtained by the Facility Infrared Spectropolarimeter at the Dunn Solar Telescope, oscillations with periods of the order of 5 min were detected at varying atmospheric heights by examining Si 10827 Å line bisector velocities. Spectropolarimetric inversions, coupled with the spatially resolved root mean square bisector velocities, allowed the wave energy fluxes to be estimated as a function of atmospheric height for each pore. We find propagating magnetoacoustic sausage mode waves with energy fluxes on the order of 30kWm-2 at an atmospheric height of 100 km, dropping to approximately 2kWm-2 at an atmospheric height of around 500 km. The cross-sectional structuring of the energy fluxes reveals the presence of both body- A nd surface-mode sausage waves. Examination of the energy flux decay with atmospheric height provides an estimate of the damping length, found to have an average value across all five pores of L d ≈ 268km, similar to the photospheric density scale height. We find the damping lengths are longer for body mode waves, suggesting that surface mode sausage oscillations are able to more readily dissipate their embedded wave energies. This work verifies the suitability of solar pores to act as efficient conduits when guiding magnetoacoustic wave energy upwards into the outer solar atmosphere. This article is part of the Theo Murphy meeting issue 'High-resolution wave dynamics in the lower solar atmosphere'.

Original languageEnglish
Article number20200172
Number of pages19
JournalPhilosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
Volume379
Issue number2190
Early online date21 Dec 2020
DOIs
Publication statusPublished - 08 Feb 2021

Bibliographical note

Funding Information:
Data accessibility. The data used in this paper are from the observing campaign entitled ‘The Influence of Magnetism on Solar and Stellar Atmospheric Dynamics’ (NSO-SP proposal T1081; principal investigator: D.B.J.), which employed the ground-based Dunn Solar Telescope, USA, during July 2016. The Dunn Solar Telescope at Sacramento Peak/NM was operated by the National Solar Observatory (NSO). NSO is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under cooperative agreement with the National Science Foundation (NSF). Additional supporting observations were obtained from the publicly available NASA’s Solar Dynamics Observatory (https://sdo.gsfc.nasa.gov) data archive, which can be accessed via http://jsoc.stanford.edu/ajax/lookdata.html. The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.

Funding Information:
Authors’ contributions. D.B.J. carried out the experiments and conceived of and designed the study. C.A.G.-M. performed the data reduction and scientific analysis, with assistance from D.B.J., S.D.T.G., P.H.K., C.B., S.J. and B.R.C. C.A.G.-M. drafted the manuscript, with theoretical input provided by J.M.R. and T.V.D. All authors read and approved the manuscript. Competing interests. We declare we have no competing interests. Funding. This study was supported by Invest NI and Randox Laboratories Ltd. Research & Development Grant (059RDEN-1); European Union’s Horizon 2020 research and innovation programme (grant agreement no. 682462); Research Council of Norway through its Centres of Excellence scheme (project no. 262622); European Union’s Horizon 2020 research and innovation programme (grant agreement no. 724326); Research Council of Norway (project no. 262622) and The Royal Society (grant no. Hooke18b/SCTM). Acknowledgements. C.A.G.-M., D.B.J. and S.D.T.G. are grateful to Invest NI and Randox Laboratories Ltd. for the award of a Research & Development Grant (059RDEN-1) that allowed the computational techniques employed to be developed. S.J. acknowledges support from the European Research Council under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 682462) and from the Research Council of Norway through its Centres of Excellence scheme (project no. 262622). J.M.R. and T.V.D. were supported by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 724326). T.V.D. received further support from the C1 grant TRACEspace of Internal Funds KU Leuven (number C14/19/089). The space-based data employed in this work is courtesy of NASA/SDO and the AIA, EVE and HMI science teams. The authors wish to acknowledge scientific discussions with the Waves in the Lower Solar Atmosphere (WaLSA; www.WaLSA.team) team, which is supported by the Research Council of Norway (project number 262622), and The Royal Society through the award of funding to host the Theo Murphy Discussion Meeting ‘High resolution wave dynamics in the lower solar atmosphere’ (grant Hooke18b/SCTM).

Publisher Copyright:
© 2020 The Author(s).

Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.

Keywords

  • Sun: Atmosphere
  • Sun: Magnetic fields
  • Sun: Oscillations
  • Sun: Photosphere
  • sunspots
  • techniques: Polarimetric

ASJC Scopus subject areas

  • Mathematics(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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