Abstract
Spicules are dynamic jets propelled upwards (at speeds of ∼20 km s-1) from the solar ‘surface’ (photosphere) into the magnetized low atmosphere of the Sun1,2,3. They carry a mass flux of 100 times that of the solar wind into the low solar corona4. With diameters close to observational limits (< 500 km), spicules have been largely unexplained3 since their discovery in 18775: none of the existing models3 can account simultaneously for their ubiquity, evolution, energetics and recently discovered periodicity6. Here we report a synthesis of modelling and high-spatial-resolution observations in which numerical simulations driven by observed photospheric velocities directly reproduce the observed occurrence and properties of individual spicules. Photospheric velocities are dominated by convective granulation (which has been considered before for spicule formation7,8,9,10,11) and by p-modes (which are solar global resonant acoustic oscillations visible in the photosphere as quasi-sinusoidal velocity and intensity pulsations). We show that the previously ignored p-modes are crucial: on inclined magnetic flux tubes, the p-modes leak sufficient energy from the global resonant cavity into the chromosphere to power shocks that drive upward flows and form spicules.
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References
- 1.
Beckers, J. M. Solar spicules. Sol. Phys. 3, 367–433 (1968)
- 2.
Beckers, J. M. Solar spicules. Annu. Rev. Astron. Astrophys. 10, 73–100 (1972)
- 3.
Sterling, A. C. Solar spicules: a review of recent models and targets for future observations. Sol. Phys. 196, 79–111 (2000)
- 4.
Withbroe, G. L. The role of spicules in heating the solar atmosphere: implications of EUV observations. Astrophys. J. 267, 825–836 (1983)
- 5.
Foukal, P. Solar Astrophysics 10–11 (John Wiley & Sons, New York, 1990)
- 6.
De Pontieu, B., Erdélyi, R. & de Wijn, A. G. Intensity oscillations in the upper transition region above active region plage. Astrophys. J. 595, L63–L66 (2003)
- 7.
Roberts, B. The resonant response to granular buffeting. Sol. Phys. 61, 23–34 (1979)
- 8.
Hollweg, J. V. On the origin of solar spicules. Astrophys. J. 257, 345–353 (1982)
- 9.
Sterling, A. C. & Hollweg, J. V. The rebound shock model for solar spicules—Dynamics at long times. Astrophys. J. 327, 950–963 (1988)
- 10.
Sterling, A. C. & Hollweg, J. V. A rebound shock model for solar fibrils. Astrophys. J. 343, 985–993 (1989)
- 11.
Sterling, A. C. & Mariska, J. T. Numerical simulations of the rebound shock model for solar spicules. Astrophys. J. 349, 647–655 (1990)
- 12.
Suematsu, Y., Wang, H. & Zirin, H. High-resolution observation of disk spicules: I. Evolution and kinematics of spicules in the enhanced network. Astrophys. J. 450, 411–421 (1995)
- 13.
Spruit, H. C. & Roberts, B. Magnetic flux tubes on the sun. Nature 304, 401–406 (1983)
- 14.
Scharmer, G. B., Bjelksjö, K., Korhonen, T. K., Lindberg, B. & Pettersson, B. in Innovative Telescopes and Instrumentation for Solar Astrophysics (eds Keil, S. & Avakyan, S.) 341–350 (Proc. SPIE, Vol. 4853, SPIE—The International Society for Optical Engineering, Hawaii, 2003)
- 15.
James, S. P., Erdélyi, R. & De Pontieu, B. Can ion-neutral damping help to form spicules? Astron. Astrophys. 406, 715–724 (2003)
- 16.
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. 45, 635–725 (1981)
- 17.
Schrijver, C. J. & Harvey, K. L. The photospheric magnetic flux budget. Sol. Phys. 150, 1–18 (1994)
- 18.
Scherrer, P. H. et al. The Solar Oscillations Investigation—Michelson Doppler Imager. Sol. Phys. 162, 129–188 (1995)
- 19.
Christensen-Dalsgaard, J., Gough, D. & Toomre, J. Seismology of the Sun. Science 229, 923–931 (1985)
- 20.
Cheng, Q.-Q. & Yi, Z. Oscillations in the solar atmosphere: a result of hydrodynamical simulations. Astron. Astrophys. 313, 971–978 (1996)
- 21.
Sutmann, G. & Ulmschneider, P. Acoustic wave propagation in the solar atmosphere: II. Nonlinear response to adiabatic wave excitation. Astron. Astrophys. 294, 241–251 (1995)
- 22.
Museliak, Z. E. & Ulmschneider, P. Atmospheric oscillations in solar magnetic flux tubes. I. Excitation by longitudinal waves and random pulses. Astron. Astrophys. 400, 1057–1064 (2003)
- 23.
Carlsson, M. & Stein, R. F. Does a nonmagnetic solar chromosphere exist? Astrophys. J. 440, L29–L32 (1995)
- 24.
Schrijver, C. J. & Title, A. M. The magnetic connection between the solar photosphere and the corona. Astrophys. J. 597, L165–L168 (2003)
- 25.
Schrijver, C. J. et al. A new view of the solar outer atmosphere by the transition region and coronal explorer. Sol. Phys. 187, 261–302 (1999)
- 26.
Handy, B. N. et al. The transition region and coronal explorer. Sol. Phys. 187, 229–260 (1999)
- 27.
De Moortel, I., Ireland, J., Walsh, R. W. & Hood, A. W. Longitudinal intensity oscillations in coronal loops observed with TRACE — I. Overview of measured parameters. Sol. Phys. 209, 61–88 (2002)
- 28.
Lindsey, C. et al. Extreme-infrared brightness profile of the solar chromosphere obtained during the total eclipse of 1991. Nature 358, 308–310 (1992)
- 29.
De Pontieu, B., Tarbell, T. D. & Erdélyi, R. Correlations on arcsecond scales between chromospheric and transition region emission in active regions. Astrophys. J. 590, 502–518 (2003)
- 30.
Rae, I. C. & Roberts, B. Pulse propagation in a magnetic flux tube. Astrophys. J. 256, 761–767 (1982)
Acknowledgements
This work was supported by NASA, the UK Particle Physics Research Council (PPARC) and NSF Hungary. The Swedish Solar Telescope is operated on the island of La Palma by the Royal Swedish Academy of Sciences in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. R.E. thanks M. Kéray for encouragement. We thank C.J. Schrijver, T. Tarbell, M. DeRosa and A. Title for discussions, and M. Carlsson for pointing out the importance of 3 min oscillations.
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Affiliations
Lockheed Martin Solar & Astrophysics Laboratory, 3251 Hanover Street, Org. ADBS, Building 252, Palo Alto, California 94304, USA
- Bart De Pontieu
Solar Physics and Upper-Atmosphere Research Centre, Department of Applied Mathematics, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, UK
- Robert Erdélyi
- & Stewart P. James
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The authors declare that they have no competing financial interests.
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Correspondence to Bart De Pontieu.
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