Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Confined pseudo-shocks as an energy source for the active solar corona


The Sun’s active corona requires an energy flux of ~103 W m−2 to compensate for radiative losses and to maintain its high temperature1. Plasma moves in the corona through magnetic loops2,3, which may be connected with the flows in and around sunspots4,5,6. Global energizing processes (for example, reconnection) play an important part in heating the corona7,8,9; however, energy and mass transport may also occur via shocks, waves or flows5,10,11. A full picture and the influence of such localized events, which significantly couple with various layers of the solar upper atmosphere, is still not clear. Using the Interface Region Imaging Spectrograph temporal image data of C ii 1,330 Å, we observed the presence of pseudo-shocks around a sunspot. Unlike shocks12, pseudo-shocks exhibit discontinuities only in the mass density. A two-fluid numerical simulation reproduces such confined pseudo-shocks with rarefied plasma regions lagging behind them. We find that these pseudo-shocks carry an energy of ~103 W m−2, which is enough to locally power the inner corona and also generate bulk flows (~10−5 kg m−2 s−1), contributing to the localized mass transport. If they are ubiquitous, such energized and bulky pseudo-shocks above active regions could provide an important contribution to the heating and mass transport in the overlying solar corona.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Direct imaging of the confined pseudo-shocks around a sunspot.
Fig. 2: Evolution of a pseudo-shock.
Fig. 3: Two-fluid simulations of a pseudo-shock using newly developed JOANNA code15.
Fig. 4: Total energy and mass fluxes (for protons + electrons and hydrogen atoms) in a pseudo-shock.

Similar content being viewed by others

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.


  1. Withbroe, G. L. & Noyes, R. W. Mass and energy flow in the solar chromosphere and corona. Annu. Rev. Astron. Astrophys. 15, 363–387 (1977).

    Article  ADS  Google Scholar 

  2. Feldman, U., Landi, E. & Schwadron, N. A. On the sources of fast and slow solar wind. J. Geophys. Res. 110, A07109 (2005).

    ADS  Google Scholar 

  3. Harra, L. K. et al. Outflows at the edges of active regions: contribution to solar wind formation? Astrophys. J. 676, L147–L150 (2008).

    Article  ADS  Google Scholar 

  4. Katsukawa, Y. et al. Small-scale jetlike features in penumbral chromospheres. Science 318, 1594–1597 (2007).

    Article  ADS  Google Scholar 

  5. Vissers, G. J. M., Rouppe van der Voort, L. H. M. & Carlsson, M. Evidence for a transition region response to penumbral microjets in sunspots. Astrophys. J. 811, 33–38 (2015).

    Article  ADS  Google Scholar 

  6. Tiwari, S. K., Moore, R. L., Winebarger, A. R. & Alpert, S. E. Transition-region/coronal signatures and magnetic setting of sunspot penumbral jets: Hinode (SOT/FG), Hi-C, and SDO/AIA observations. Astrophys. J. 816, 92 (2016).

    Article  ADS  Google Scholar 

  7. Cargill, P. J. & Klimchuk, J. A. Nanoflare heating of the corona revisited. Astrophys. J. 605, 911–920 (2004).

    Article  ADS  Google Scholar 

  8. Aschwanden, M. J., Winebarger, A., Tsiklauri, D. & Peter, H. The coronal heating paradox. Astrophys. J. 659, 1673–1681 (2007).

    Article  ADS  Google Scholar 

  9. Klimchuk, J. A. Key aspects of coronal heating. Phil. Trans. R. Soc. A 373, 20140256 (2015).

    Article  ADS  Google Scholar 

  10. Ryutova, M., Berger, T., Frank, Z. & Title, A. On the penumbral jetlike features and chromospheric bow shocks. Astrophys. J. 686, 1404–1419 (2008).

    Article  ADS  Google Scholar 

  11. Bharti, L., Solanki, S. K. & Hirzberger, J. Lambda-shaped jets from a penumbral intrusion into a sunspot umbra: a possibility for magnetic reconnection. Astron. Astrophys. 597, A127 (2017).

    Article  ADS  Google Scholar 

  12. Priest, E. R. Magnetohydrodynamics of the Sun (Cambridge Univ. Press, Cambridge, 2014).

  13. Crocco, L. in High Speed Aerodynamics and Jet Propulsion: Fundamentals of Gas Dynamics Vol III (ed. Emmons, H. W.) 110–130 (Princeton Univ. Press, Princeton, 1958).

  14. De Pontieu, B. et al. The interface region imaging spectrograph (IRIS). Sol. Phys. 289, 2733–2779 (2014).

    Article  ADS  Google Scholar 

  15. De Pontieu, B. et al. On the prevalence of small-scale twist in the solar chromosphere and transition region. Science 346, 1255732 (2014).

    Article  Google Scholar 

  16. Wójcik, D. P. Numerical Model of Magnetohydrodynamic Waves in the Solar Atmosphere. MSc thesis, Maria Curie-Skłodowska Univ. (2016).

  17. Konkol, P., Murawski, K. & Zaqarashvili, T. V. Numerical simulations of magnetoacoustic oscillations in a gravitationally stratified solar corona. Astron. Astrophys. 537, A96 (2012).

    Article  ADS  Google Scholar 

  18. Avrett, E. H. & Loeser, R. Models of the solar chromosphere and transition region from SUMER and HRTS observations: formation of the extreme-ultraviolet spectrum of hydrogen, carbon, and oxygen. Astrophys. J. Suppl. 175, 229–276 (2008).

    Article  ADS  Google Scholar 

  19. Kuźma, B. et al. 2-fluid numerical simulations of solar spicules. Astrophys. J. 849, 78 (2017).

    Article  ADS  Google Scholar 

  20. Oliver, R., Soler, R., Terradas, J. & Zaqarashvili, T. V. Dynamics of coronal rain and descending plasma blobs in solar prominences. II. Partially ionized case. Astrophys. J. 818, 128 (2016).

    Article  ADS  Google Scholar 

  21. Khomenko, E. On the effects of ion-neutral interactions in solar plasmas. Plasma Phys. Contr. Fusion 59, 014038 (2017).

    Article  ADS  Google Scholar 

  22. Edwards, S. J., Parnell, C. E., Harra, L. K., Culhane, J. L. & Brooks, D. H. A comparison of global magnetic field skeletons and active-region upflows. Sol. Phys. 291, 117–142 (2016).

    Article  ADS  Google Scholar 

  23. Jess, D. et al. Alfvén waves in the lower solar atmosphere. Science 323, 1582–1585 (2009).

    Article  ADS  Google Scholar 

  24. McIntosh, S. et al. Alfvénic waves with sufficient energy to power the quiet solar corona and fast solar wind. Nature 475, 477–480 (2011).

    Article  ADS  Google Scholar 

  25. Srivastava, A. K. et al. High-frequency torsional Alfvén waves as an energy source for coronal heating. Sci. Rep. 7, 43147 (2017).

    Article  ADS  Google Scholar 

  26. Cirtain, J. W. et al. Energy release in the solar corona from spatially resolved magnetic braids. Nature 493, 501–503 (2013).

    Article  ADS  Google Scholar 

  27. Yang, S., Zhang, J., Jiang, F. & Xiang, Y. Oscillating light wall above a sunspot light bridge. Astrophys. J. 804, L27 (2015).

    Article  ADS  Google Scholar 

  28. Tian, H. et al. Observations of subarcsecond bright dots in the transition region above sunspots with the interface region imaging spectrograph. Astrophys. J. 790, L29 (2014).

    Article  ADS  Google Scholar 

  29. Alpert, S. E., Tiwari, S. K., Moore, R. L., Winebarger, A. R. & Savage, S. L. Hi-C observations of sunspot penumbral bright dots. Astrophys. J. 822, 35 (2016).

    Article  ADS  Google Scholar 

Download references


A.K.S. and B.N.D. acknowledge the RESPOND-ISRO (DOS/PAOGIA205-16/130/602) project. A.K.S. acknowledges the SERB-DST project (YSS/2015/000621) grant, and the Advanced Solar Computational and Analyses Laboratory (ASCAL). Armagh Observatory and Planetarium is grant-aided by the Northern Ireland Department for Communities. J.G.D. acknowledges the DJEI/DES/SFI/HEA Irish Centre for High-End Computing for provision of computing facilities and support. J.G.D. also thanks the STFC for PATT travel and subsistence and the SOLARNET project, which is supported by the European Commission’s FP7 Capacities Programme under grant agreement number 312495, for travel and subsistence. M.S. acknowledges support from ‘Progetti di ricerca INAF di Rilevante Interesse Nazionale’ (PRIN-INAF 2014) and project 2012P2HRCR ‘Il sole attivo ed i suoi effetti sul clima dello spazio e della terra’ (PRIN MIUR 2012) grants, funded by the Italian National Institute for Astrophysics (INAF) and Ministry of Education, Universities and Research (MIUR), respectively. Work by K.M., B.K. and D.P.W. was supported financially by projects at the National Science Centre, Poland (grant numbers 2014/15/B/ST9/00106 and 2017/25/B/ST9/00506). T.V.Z. was supported by the Austrian Science Fund ‘FWF’ project P30695-N27 and Georgian Shota Rustaveli National Science Foundation project DI-2016-17. Z.E.M. acknowledges support from the Alexander von Humboldt Foundation. The authors express thanks to A. Kaczmarczyk for assistance with creating the Adobe illustrations. They also acknowledge the use of IRIS and Solar Dynamics Observatory/Atmospheric Imaging Assembly observations in this work.

Author information

Authors and Affiliations



A.K.S. led the project by defining the novel science case, analysing and making the IRIS observations, and writing the paper. K.M., B.K. and D.P.W. constructed the numerical model based on the two-fluid JOANNA code, which was developed by D.P.W. All co-authors (A.K.S., K.M., B.N.D., J.G.D., T.V.Z., M.S., Z.E.M., B.K., D.P.W. and P.K.) participated in studying the science and editing the draft.

Corresponding author

Correspondence to Abhishek Kumar Srivastava.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher's note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Srivastava, A.K., Murawski, K., Kuźma, B. et al. Confined pseudo-shocks as an energy source for the active solar corona. Nat Astron 2, 951–956 (2018).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing