Characterization of shock wave signatures at millimetre wavelengths from Bifrost simulations: Shock wave signatures at mm-wavelengths

Henrik Eklund*, Sven Wedemeyer, Ben Snow, David B. Jess, Shahin Jafarzadeh, Samuel D.T. Grant, Mats Carlsson, Mikołaj Szydlarski

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


Observations at millimetre wavelengths provide a valuable tool to study the small-scale dynamics in the solar chromosphere. We evaluate the physical conditions of the atmosphere in the presence of a propagating shock wave and link that to the observable signatures in mm-wavelength radiation, providing valuable insights into the underlying physics of mm-wavelength observations. A realistic numerical simulation from the three-dimensional radiative magnetohydrodynamic code Bifrost is used to interpret changes in the atmosphere caused by shock wave propagation. High-cadence (1 s) time series of brightness temperature (T b) maps are calculated with the Advanced Radiative Transfer code at the wavelengths 1.309 mm and 1.204 mm, which represents opposite sides of spectral band 6 of the Atacama Large Millimeter/submillimeter Array (ALMA). An example of shock wave propagation is presented. The brightness temperatures show a strong shock wave signature with large variation in formation height between approximately 0.7 and 1.4 Mm. The results demonstrate that millimetre brightness temperatures efficiently track upwardly propagating shock waves in the middle chromosphere. In addition, we show that the gradient of the brightness temperature between wavelengths within ALMA band 6 can potentially be used as a diagnostics tool in understanding the small-scale dynamics at the sampled layers. This article is part of the Theo Murphy meeting issue 'High-resolution wave dynamics in the lower solar atmosphere'.

Original languageEnglish
Article number20200185
Number of pages15
JournalPhilosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
Issue number2190
Early online date21 Dec 2020
Publication statusPublished - 08 Feb 2021

Bibliographical note

Funding Information:
Data accessibility. The Bifrost simulation with 10 s cadence is publicly available at: simulations. Authors’ contributions. M.S. and M.C. performed the M.H.D. simulations and radiative transfer computations. H.E. performed scientific analysis, with assistance from S.W., B.S., D.B.J., S.J., S.D.T.G. and M.C. H.E. drafted the manuscript. All authors read and approved the manuscript. Competing interests. We declare we have no competing interests. Funding. This work is supported by the SolarALMA project, which has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 682462) and by the Research Council of Norway through its Centres of Excellence scheme, project number 262622 (Rosseland Centre for Solar Physics). The development of the Advanced Radiative Transfer (ART) code was supported by the PRACE Preparatory Access Type D program (proposal 2010PA3776). Grants of computing time from the Norwegian Programme for Supercomputing are acknowledged. B.S. is supported by STFC research grant no. ST/R000891/1. D.B.J. and S.D.T.G. are supported by an Invest NI and Randox Laboratories Ltd. Research & Development grant no. (059RDEN-1).

Funding Information:
Acknowledgements. 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). We also acknowledge collaboration with the Solar Simulations for the Atacama Large Millimeter Observatory Network (SSALMON, The support by M. Krotkiewski from USIT, University of Oslo, Norway, for the technical development of ART is gratefully acknowledged. B.S., D.B.J., S.J. and S.D.T.G. wish to acknowledge scientific discussions with the Waves in the Lower Solar Atmosphere (WaLSA; team, which is supported by the Research Council of Norway (project no. 262622) and the Royal Society (award no. Hooke18b/SCTM). The Advanced Radiative Transfer (ART) code was developed by Jaime de la Cruz Rodriguez and Mikolaj Szydlarski and optimised with the help of a PRACE Preparatory Access Type D program (proposal 2010PA3776) supported by M. Krotkiewski from USIT, University of Oslo, Norway.

Publisher Copyright:
© 2020 The Author(s).

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


  • methods: Numerical
  • shock waves
  • Sun: Chromosphere
  • Sun: Photosphere
  • Sun: Radio radiation

ASJC Scopus subject areas

  • General Mathematics
  • General Engineering
  • General Physics and Astronomy


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