Abstract
High-resolution images obtained in Hα with the new Swedish Solar Telescope at La Palma, Spain, have been used for studies of fine-scale threads in solar filaments. The widths of the thin threads are ≤0.3 arcsec. The fact that the width of the thinnest threads is comparable to the diffraction limit of the telescope of about 0.14 arcsec, at the wavelength of Hα, suggests that even thinner threads may exist. Assuming that the threads represent thin magnetic strings, we conclude that only a small fraction of these are filled with observable absorbing plasma, at a given time. The absorbing plasma is continuously flowing along the thread structures at velocities 15± 10 kms−1, which suggests that the flows must be field-aligned. In one case where a bundle of thin threads appears to be rooted in the nearby photosphere, we find that the individual threads connects with intergranular, dark lanes in the photosphere. We do not find signs of typical network fields at the ‘roots’ of the fine threads, as normally evidenced by bright points in associated G-band images. It is suggested that filament threads are rooted in relatively weak magnetic fields.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Antiochos, S. K., MacNeice, P. J., and Spicer, D. S.: 2000, Astrophys. J. 536, 494.
Berger, T. E., Löfdahl, M. G., Shine, R. S., and Title, A. M.: 1998, Astrophys. J. 495, 973.
Berger, T. E. and Title, A. M.: 2001, Astrophys. J. 553, 449.
Bommier, V., Landi Degl’Innocenti, E., Leroy, J.-L., and Sahal-Brechot, S.: 1994, Solar Phys. 154, 231.
de Boer, C. R., Stellmacher G., and Wiehr, E.: 1998, Astron. Astrophys. 334, 280.
Dunn, R. B.: 1960, Ph.D. thesis, Harvard University.
Engvold, O.: 1976, Solar Phys. 49, 283.
Engvold, O.: 2001, in Paul Murdin (ed.), Encyclopedia of Astronomy and Astrophysics, Institute of Physics Publishing, p. 2695.
Forbes, T. and Malherbe, J. M.: 1986, Astron. Astrophys. Lett. 302, L67.
Karpen, J. T., Antiochos, S. K., Hohensee, M., Klimchuk, J. A., and MacNeise, P. J.: 2001, Astrophys. J. Lett. 553, L85.
Leroy, J.-L.: 1988, in Proceedings of the Ninth Sacramento Peak Summer Symposium, Sunspot NM, on Solar and Stellar Coronal Structure and Dynamics, National Solar Observatory, p. 422.
Lin, Y., Engvold, O., and Wiik, J. E.: 2003, Solar Phys. 216, 109.
Lin, Y., Wiik, J. E., Engvold, O., Rouppe van der Voort, L. H. M., and Frank, Z. A.: 2005, Solar Phys., in press.
Löfdahl, M. G.: 2002, in Bones, Fiddy, and Millane (eds.), Proceedings of the SPIE 4792 on Image Reconstruction from Incomplete Data II, p. 146.
Martin, S. F.: 1998, Solar Phys. 182, 107.
Martin, S. F.: 2001, in Murdin, P. (ed.), Encyclopedia of Astronomy and Astrophysics, Institute of Physics Publishing, p. 2698.
Martin, S. F. and Echols, C. R.: 1994, in R. J. Rutten and C. J. Schrijver (eds.), Solar Surface Magnetism, (NATO ASI Ser. C-433, Kluwer Academic Publishers, Dordrecht, p. 339.
Menzel, D. H. and Wolbach, J. G.: 1960a, Sky Telescope 20, 330.
Menzel, D. H. and Wolbach, J. G.: 1960b, Sky Telescope 20, 252.
November, L. J. and Simon, G. W.: 1988, Astrophys. J. 333, 427.
Priest, E., van Ballegooijen, A., and MacKay, D.: 1996, Astron. Astrophys. 460, 530.
Rompolt, B. and Bogdan, T.: 1986, in Poland, A. I. (ed.), Coronal and Prominence Plasmas, NASA Conf. Publ. 2442, p. 81.
Rutten, R. J., Kiselman, D., Rouppe van der Voort, L. H. M., and Plez, B.: 2001, in Sigwarth, M. (ed.), ASP Proceedings on Theory, Observation, and Instrumentation, 20TH NSO/Sac Summer Workshop, Vol. 236, Series 236, p. 445.
Sánchez Almeida, J., Asensio Ramos, A., Trujillo Bueno, J., and Cernicharo, J.: 2001, Astrophys. J. 555, 978.
Scharmer, G. B., Bjelksjö, K., Korhonen, T. K., Lindberg, B., and Pettersson, B.: 2003a, in S. Keil and S. Avakyan (eds.), Innovative Telescopes and Instrumentation for Solar Astrophysics, Proc. SPIE 4853, 341.
Scharmer, G. B., Dettori, P. M., Löfdahl, M. G., and Shand, M.: 2003b, in S. Keil and S. Avakyan (eds.), Innovative Telescopes and Instrumentation for Solar Astrophysics, Proc. SPIE 4853, 370.
Schmieder, B., Raadu, M. A., and Wiik, J. E.: 1991, Astron. Astrophys. 252, 353.
Schüssler, M., Shelyag, S., Berdyugina, S. V., Vögler, A., and Solanki, S. K.: 2003, Astrophys. J. 597, L173.
Shelyag, S., Schüssler, M., Solanki, S. K., Berdyugina, S. V., and Vögler, A.: Astron. Astrophys. 427, 335, in press.
Shine, R. A., Simon, G. W., and Hurlburt, N. E.: 2000, Solar Phys. 193, 313.
Spruit, H. C.: 1976, Solar Phys. 50, 269.
Tandberg-Hanssen, E.: 1995, The Nature of Solar Prominence, Kluwer Academic Pulishers.
Title, A. M. and Rosenberg, W. J.: 1981, Optical Engineering 20, 815.
Wang, Y.-M.: 2001, Astrophys. J. 560, 456.
Yi, Z.: 1992, Ph.D. thesis, University of Oslo, p. 53.
Yi, Z. and Molowny-Horas, R.: 1995, Astron. Astrophys. 295, 199.
Zirker, J. B., Engvold, O., and Martin, S. F.: 1998, Nature 396, 440.
Zirker, J. B. and Koutchmy, S.: 1990, Solar Phys. 131, 107.
Zirker, J. B. and Koutchmy, S.: 1991, Solar Phys. 127, 109.
Zong, W. G., Tang, Y. H., Fang, C., Mein, P., Mein, N., and Xu, A. A.: 2003, Astron. Astrophys. 412, 267.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Lin, Y., Engvold, O., der Voort, L.R.v. et al. Thin Threads of Solar Filaments. Sol Phys 226, 239–254 (2005). https://doi.org/10.1007/s11207-005-6876-3
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/s11207-005-6876-3