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High-frequency acoustic waves are not sufficient to heat the solar chromosphere

Nature volume 435, pages 919–921 (2005)Cite this article

Abstract

One of the main unanswered questions in solar physics is why the Sun's outer atmosphere is hotter than its surface. Theory predicts abundant production of high-frequency (10–50 mHz) acoustic waves in subsurface layers of the Sun1, and such waves are believed by many to constitute the dominant heating mechanism of the chromosphere (the lower part of the outer solar atmosphere) in non-magnetic regions2,3,4. Such high-frequency waves are difficult to detect because of high-frequency disturbances in Earth's atmosphere (seeing) and other factors. Here we report the detection of high-frequency waves, and we use numerical simulations to show that the acoustic energy flux of these waves is too low, by a factor of at least ten, to balance the radiative losses in the solar chromosphere. Acoustic waves therefore cannot constitute the dominant heating mechanism of the solar chromosphere.

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Figure 1: Power of observed 1,600 Å TRACE relative intensity fluctuations.
Figure 2: Power of the acoustic energy fluxes in the simulations.
Figure 3: Simulated and observed 1,600 Å TRACE intensity fluctuations.
Figure 4: Simulated and derived acoustic energy fluxes at a height of 400 km.

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References

  1. Musielak, Z. E., Rosner, R., Stein, R. F. & Ulmschneider, P. On sound generation by turbulent convection: a new look at old results. Astrophys. J. 423, 474–487 (1994)

    Article  ADS  Google Scholar 

  2. Ulmschneider, P. Acoustic heating of stellar chromospheres and coronae. Astron. Soc. Pacif. Conf. Ser. 9, 3–14 (1990)

    ADS  Google Scholar 

  3. Ulmschneider, P., Theurer, J. & Musielak, Z. E. Acoustic wave energy fluxes for late-type stars. Astron. Astrophys. 315, 212–221 (1996)

    ADS  Google Scholar 

  4. Fawzy, D., Rammacher, W., Ulmschneider, P., Musielak, Z. E. & Stepien, K. Acoustic and magnetic wave heating in stars. I. Theoretical chromospheric models and emerging radiative fluxes. Astron. Astrophys. 386, 971–982 (2002)

    Article  ADS  Google Scholar 

  5. Fossum, A. & Carlsson, M. Response functions of the UV filters of TRACE and the detectability of high frequency acoustic waves. Astrophys. J. (in the press)

  6. Handy, B. N. et al. The transition region and coronal explorer. Sol. Phys. 187, 229–260 (1999)

    Article  ADS  CAS  Google Scholar 

  7. Carlsson, M. & Stein, R. F. Does a nonmagnetic solar chromosphere exist? Astrophys. J. 440, 29–32 (1995)

    Article  ADS  Google Scholar 

  8. Carlsson, M. & Stein, R. F. Formation of solar calcium H and K bright grains. Astrophys. J. 481, 500–514 (1997)

    Article  ADS  CAS  Google Scholar 

  9. Carlsson, M. & Stein, R. F. Dynamic hydrogen ionization. Astrophys. J. 572, 626–635 (2002)

    Article  ADS  CAS  Google Scholar 

  10. Dorfi, E. A. & Drury, L. O. Simple adaptive grids for 1-D initial value problems. J. Comput. Phys. 69, 175–195 (1987)

    Article  ADS  Google Scholar 

  11. Gustafsson, B. A Fortran program for calculating “continous” absorption coefficients of stellar atmospheres. Uppsala Astr. Obs. Ann 5(6), 1–31 (1973)

    Google Scholar 

  12. Kurucz, R. L. & Bell, B. Atomic Line Data (CD-ROM 23, Smithsonian Astrophysical Observatory, Cambridge, Massachusetts, 1995)

    Google Scholar 

  13. van Regemorter, H. Rate of collisional excitation in stellar atmospheres. Astrophys. J. 136, 906–915 (1962)

    Article  ADS  Google Scholar 

  14. Tobiska, W. K. Revised solar extreme ultraviolet flux model. J. Atmos. Terr. Phys. 53, 1005–1018 (1991)

    Article  ADS  CAS  Google Scholar 

  15. Vernazza, J. E., Avrett, E. H. & Loeser, R. Structure of the solar chromosphere. III—Models of the EUV brightness components of the quiet-sun. Astrophys J. Suppl. Ser. 45, 635–725 (1981)

    Article  ADS  CAS  Google Scholar 

  16. Goldreich, P., Murray, N. & Kumar, P. Excitation of solar p-modes. Astrophys. J. 424, 466–479 (1994)

    Article  ADS  Google Scholar 

  17. Stein, R. F. & Nordlund, Å. Solar oscillations and convection. II. Excitation of radial oscillations. Astrophys. J. 546, 585–603 (2001)

    Article  ADS  Google Scholar 

  18. Carlsson, M. & Stein, R. F. in Proc. Magnetic Coupling of the Solar Atmosphere Euroconf (ed. Sawaya-Lacoste, H.) 293–300 (IAU Colloquium 188, ESA SP-505, ESA, Noordwijk, 2002)

    Google Scholar 

  19. Sanchez Almeida, J. On the Sr I 4607 Hanle depolarization signals in the quiet Sun. Astron. Astrophys. (in the press)

  20. Krijger, J. M. et al. Dynamics of the solar chromosphere. III. Ultraviolet brightness oscillations from TRACE. Astron. Astrophys. 379, 1052–1082 (2001)

    Article  ADS  CAS  Google Scholar 

Download references

Acknowledgements

This work was supported by the Research Council of Norway and by a grant of computing time from the Program for Supercomputing. We thank T. Tarbell, B. De Pontieu and the TRACE instrument team for their support.

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  1. Institute of Theoretical Astrophysics, University of Oslo, PB 1029, 0315, Blindern, Oslo, Norway

    Astrid Fossum & Mats Carlsson

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  1. Astrid Fossum
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Correspondence to Astrid Fossum.

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Fossum, A., Carlsson, M. High-frequency acoustic waves are not sufficient to heat the solar chromosphere. Nature 435, 919–921 (2005). https://doi.org/10.1038/nature03695

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