Abstract
Careful examination of 43 soft X-ray loops observed by Yohkoh has revealed a number of interesting properties of the loop cross section. First, the loops tend to be only slightly (≈ 30%) wider at their midpoints than at their footpoints, implying less-than-expected expansion of the magnetic field. Second, the variation of width along each loop tends to be modest, implying that the cross section has an approximately circular shape. And third, cross-axis intensity profiles tend to be singly-peaked and simple, implying that the cross section is approximately uniformly filled on resolvable scales. We conclude that the energy which heats the plasma is either dissipated axially symmetrically on a scale equal to a loop diameter (≈ 11000 km) or else is dissipated with any spatial structure, but on a scale much smaller than a loop diameter, and then transported laterally in an axisymmetric fashion (perhaps via conduction along chaotic field lines). In their present form, none of the theoretical ideas concerning the magnetic structure and heating of loops are obviously capable of explaining all of the observed properties.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Alexander, D. and Katsev, S.: 1996, Solar Phys. 167, 153.
Antiochos, S. K. and Sturrock, P. A.: 1976, Solar Phys. 49, 359.
Aschwanden, M. J. et al.: 1999, Astrophys. J. 515, 842.
Aschwanden, M. J. et al.: 2000, Astrophys. J. 531, 1129.
Bray, R. J., Cram, L. E., Durrant, C. J., and Loughhead, R. E.: 1991, Plasma Loops in the Solar. Corona, Cambridge University Press, Cambridge.
Davila, J. M.: 1987, Astrophys. J. 317, 514.
Dixon, W. W., Klimchuk, J. A., Sturrock, P. A., and Lemen, J. R.: 1991, in Y. Uchida, R. C. Canfield, T. Watanabe, and E. Hiei (eds.), Flare Physics in Solar Activity Maximum 22, Springer-Verlag, Berlin, p. 297.
Dowdy, J. F., Emslie, A. G., and Moore, R. L.: 1987, Solar Phys. 112, 255.
Galsgaard, K. and Nordlund, A.: 1996, J. Geophys. Res. 101, 13,445.
Galsgaard, K. and Nordlund, A.: 1997, J. Geophys. Res. 102, 219.
Gary, G. A.: 1997, Solar Phys. 174, 241.
Golub, L. et al.: 1990, Nature 344, 842.
Jiao, L., MeClymont, A. N., and Mikić, Z.: 1997, Solar Phys. 174, 311.
Kano, R. and Tsuneta, S.: 1995, Astrophys. J. 454, 934.
Klimchuk, J. A. and Porter, L. J.: 1995, Nature 377, 131.
Klimchuk, J. A., Norton, D., and Antiochos, S. K.: 2000, Astrophys. J., submitted.
Klimchuk, J. A., Lemen, J. R., Feldman, U., Tsuneta, S., and Uchida, Y.: 1992, Publ. Astron. Soc. Japan 44, L181.
Litwin, C. and Rosner, R.: 1993, Astrophys. J. 412, 375.
Longcope, D. W. and Sudan, R. N.: 1994, Astrophys. J. 437, 491.
Mandrini, C. H., Démoulin, P., and Klimchuk, J. A.: 2000, Astrophys. J. 530, 999.
Mariska, J. T.: 1984, Astrophys. J. 281, 435.
Martens, P. C., Acton, L. W., and Lemen, J. R.: 1995, Solar Phys. 157, 141.
MeClymont, A. N. and Mikić, Z.: 1994, Astrophys. J. 422, 899.
McTieman, J. and Petrosian, V.: 1990, Astrophys. J. 359, 524.
Mikić, Z., Schnack, D. D., and Van Hoven, G.; 1989, Astrophys. J. 338, 1148.
Ofman, L., Klimchuk, J. A., and Davila, J. M.: 1998, Astrophys. J. 493, 474.
Orrall, F. Q. (ed.): 1981, Solar Active Regions, Colorado Associated University Press, Boulder.
Parker, E. N.: 1983, Astrophys. J. 264, 642.
Poletto, G. et al.: 1975, Solar Phys. 44, 83.
Porter, L. J. and Klimchuk, J. A.: 1995, Astrophys. J. 454, 499.
Porter, J. G., Falconer, D. A., and Moore, R. L.: 1998, in T.-D. Guyenne (ed.), Solar Jets and Coronal. Plumes, ESA Publications, The Netherlands, p. 147.
Porter, L. J., Klimchuk, J. A., and Sturrock, P. A.: 1994, Astrophys. J. 435, 482.
Robertson, J. A., Hood, A. W., and Lothian, R. M.: 1992, Solar Phys. 137, 273.
Tsuneta, S. et al.: 1991, Solar Phys. 136, 37.
Sakurai, T. and Yan, Y.: 1996, in X. S. Feng, F. S. Wei, and M. Dryer (eds.), Proceedings of the Third. SOLTIP Symposium, Int. Academic Publishers, p. 1.
Schrijver, C. J., Lemen, J. R., and Mewe, R.: 1989, Astrophys. J. 341, 484.
Vesecky, J. F., Antiochos, S. K., and Underwood, J. H.: 1979, Astrophys. J. 233, 987.
Wang, H. and Sakurai, T.: 1998, Publ. Astron. Soc. Japan 50, 111.
Watko, J. A. and Klimchuk, J. A.: 2000, Solar Phys. 193, 77 (this issue).
Yan, Y. and Sakurai, T.: 1997, Solar Phys. 174, 65.
Zweibel, E. G. and Boozer, A. H.: 1985, Astrophys. J. 295, 642.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2001 Springer Science+Business Media Dordrecht
About this paper
Cite this paper
Klimchuk, J.A. (2001). Cross-Sectional Properties of Coronal Loops. In: Engvold, O., Harvey, J.W. (eds) Physics of the Solar Corona and Transition Region. Springer, Dordrecht. https://doi.org/10.1007/978-94-010-0860-0_4
Download citation
DOI: https://doi.org/10.1007/978-94-010-0860-0_4
Publisher Name: Springer, Dordrecht
Print ISBN: 978-94-010-3846-1
Online ISBN: 978-94-010-0860-0
eBook Packages: Springer Book Archive