Downward pumping of magnetic flux as the cause of filamentary structures in sunspot penumbrae

Nature

Volumn 420, Issue 6914, 2002, Pages 390-393

  Thomas, John H ^a,b   Weiss, Nigel O ^a   Tobias, Steven M ^c   Brummell, Nicholas H ^d  

^a UNIVERSITY OF CAMBRIDGE   (United Kingdom)

^b UNIVERSITY OF ROCHESTER   (United States)

^c UNIVERSITY OF LEEDS   (United Kingdom)

^d UNIVERSITY OF COLORADO   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

BUOYANCY; HEAT CONVECTION; MAGNETIC FIELD EFFECTS;

FILAMENTARY STRUCTURES;

MAGNETIC FLUX;

CONVECTION; MAGNETIC FIELD; SUNSPOT;

ARTICLE; ASTRONOMY; COMPRESSION; MAGNETIC FIELD; MOLECULAR INTERACTION; PLUME; PRIORITY JOURNAL; SIMULATION; STRUCTURE ANALYSIS; SURFACE PROPERTY; VELOCITY;

UMBRA;

EID: 0037191785     PISSN: 00280836     EISSN: None     Source Type: Journal    
DOI: 10.1038/nature01174     Document Type: Article

References (27)

1. Thomas, J. H. & Weiss, N. O. (eds) Sunspots: Theory and Observations NATO ASI C 375 (Kluwer, Dordrecht, 1992).
2. Schmieder, B., del Toro Iniesta, J. C. & Vázquez, M. (eds) Advances in the Physics of Sunspots Astronomical Society of the Pacific Cònference Series 118, (San Francisco, 1997).
3. Degenhardt, D. & Wiehr, E. Spatial variation of the magnetic field inclination in a sunspot penumbra. Astron. Astrophys. 252, 821-826 (1991).
4. Solanki, S. K. & Montavon, C. A. P. Uncombed fields as the source of broad-band circular polarization of sunspots. Astron. Astrophys. 275, 283-292 (1993).
5. Title, A. M. et al. On the magnetic and velocity field geometry of simple sunspots. Astrophys. J. 403, 780-796 (1993).
6. Lites, B. W., Elmore, D. F., Seagraves, P. & Skumanich, A. Stokes profile analysis and vector magnetic fields. VI. Fine-scale structure of a sunspot. Astrophys. J. 418, 928-942 (1993).
7. Solanki, S. K., Montavon, C. A. P. & Livingston, W. Infrared lines as a probe of solar magnetic features. VII. On the nature of the Evershed effect in sunspots. Astron. Astrophys. 283, 221-231 (1994).
8. Rimmele, T. R. Sun center observations of the Evershed effect. Astrophys. J. 445, 511-516 (1995).
9. Stanchfield, D. C. H. II, Thomas, J. H. & Lites, B. W. The vector magnetic field. Evershed flow, and intensity in a sunspot. Astrophys. J. 477, 485-494 (1997).
10. Westendorp Plaza, C. et al. Evidence for a downward mass flux in the penumbral region of a sunspot. Nature 389, 47-49 (1997).
11. Rüedi, I., Solanki, S. K. & Keller, C. U. Infrared lines as probes of solar magnetic features. XV Evershed flow in cool, weak penumbral fields. Astron. Astrophys. 348, L37-L40 (1999).
12. Schlichenmaier, R. & Schmidt, W. Flow geometry in a sunspot penumbra. Astron. Astrophys. 358, 1122-1132 (2000).
13. Martinez Pillet, V. Spectral signature of uncombed magnetic fields. Astron. Astrophys. 361, 734-742 (2000).
14. Westendorp Plaza, C., del Toro Iniesta, J. C., Ruiz Cobo, B. & Martínez Pillet, V. Optical tomography of a sunspot. III. Velocity stratification and the Evershed effect. Astrophys. J. 547, 1148-1158 (2001).
15. Montesinos, B. & Thomas, J. H. The Evershed effect in sunspots as a siphon flow along a magnetic flux tube. Nature 390, 485-487 (1997).
16. Stein, R. F. & Nordlund, Å. Simulations of solar granulation. I. General properties. Astrophys. J. 499, 914-933 (1998).
17. Brummell, N. H., Clune, T. L. & Toomre, J. Penetration and overshooting in turbulent compressible convection. Astrophys. J. 570, 825-854 (2002).
18. Tobias, S. M., Brummell, N. H., Clune, T. L. & Toomre, J. Transport and storage of magnetic field by overshooting turbulent compressible convection. Astrophys. J. 549, 1183-1203 (2001).
19. Nordlund, Å. et al. Dynamo action in stratified convection with overshoot. Astrophys. J. 392, 647-652 (1992).
20. Brandenburg, A. et al. Magnetic structures in a dynamo simulation. J. Fluid Mech. 306, 325-352 (1996).
21. Tobias, S. M., Brummell, N. H., Clune, T. L. & Toomre, J. Pumping of magnetic fields by turbulent penetrative convection. Astrophys. J. 502, L177-L180 (1998).
22. Dorch, S. B. F. & Nordlund, Å. On the transport of magnetic fields by solar-like stratified convection. Astron. Astrophys. 365, 562-570 (2001).
23. Rucklidge, A. M., Schmidt, H. U. & Weiss, N. O. The abrupt development of penumbrae in sunspots. Mon. Not. R. Astron. Soc. 273, 491-498 (1995).
24. Schlichenmaier, R., Jahn, K. & Schmidt, H. U. A dynamical model for the penumbral fine structure and the Evershed effect in sunspots. Astrophys. J. 493, L121-L124 (1998).
25. Tildesley, M. J. On the origin of filamentary structure in sunspot penumbrae: Linear instabilities. Mon. Not. R. Astron. Soc. (submitted).
26. Shine, R. A. & Title, A. M. in Encyclopedia of Astronomy and Astrophysics 3209-3212 (Nature Publishing Group, London, and Institute of Physics Publishing, Bristol, 2001).
27. Harvey, J. & Harvey, K. Observations of moving magnetic features near sunspots. Sol. Phys. 28, 61-71 (1973).