Abstract
Newly formed stars have magnetic fields provided by the compression of the interstellar field, and contrary to a widely accepted idea these fields are not destroyed by convective motions. For the same reason, the fallacy of ‘turbulent diffusion’, turbulent dynamo action is not possible in any star. Thus all stellar magnetic fields have a common origin, and persist throughout the lifetime of each star, including degenerate phases. This common origin, and a general similarity in stellar evolutionary processes, suggest that the fields may develop similar structural characteristics and MHD effects. This would open new possibilities of coordinating the studies of different types of stars and relating them to solar physics which has tended to become isolated from general stellar physics. As an initial step we consider three features of solar magnetic fields and their MHD effects. First, the solar magnetic field comprises two separate components: a poloidal field and a toroidal field. The former is a dipole field, permeating the entire Sun and closely aligned with the rotational axis; at the surface it is always concealed by much stronger elements of the toroidal field. The latter is probably wound from the former by differential rotation at latitudes below about 35°, where sections emerge through the solar surface and are then carried polewards. The second feature of solar magnetic fields is that all flux is concentrated into flux tubes of strength some kG, isolated within a much larger volume of non-magnetic plasma. The third feature is that the flux tubes are helically twisted into flux ropes (up to ≳1022Mx) and smaller elements ranging down to flux fibres (≲ 1018Mx). Some implications of similar features in other stars are discussed.
Similar content being viewed by others
References
Angel, J. R. P.: 1978,Ann. Rev. Astron. Astrophys. 16, 487.
Babcock, H. W.: 1961,Astrophys. J. 133, 572.
Belvedere, G., Paterno, L., and Stix, M.: 1980,Astron. Astrophys. 91, 328.
Cowling, T. G.: 1981,Ann. Rev. Astron. Astrophys. 19, 115.
Galloway, D. J. and Weiss, N. O.: 1981,Astrophys. J. 243, 945.
Godoli, G.: 1976, in V. Bumba and J. Kleczek (eds.), ‘Basic Mechanicsms of Solar Activity’,IAU Symp. 71, 421.
Harvey, J. W.: 1977, in E. Müller (ed.),Hightlights of Astronomy 4, D. Reidel Publ. Co., Dordrecht, Holland.
Howard, R.: 1977,Ann. Rev. Astron. Astrophys. 15, 153.
Larson, R. B.: 1972,Monthly Notices Roy. Astron. Soc. 157, 271.
Leavy, E. H. and Rose, W. K.: 1974,Nature 250, 40.
Linsky, J.: 1977, in O. R. White (ed.),The Solar Output and its Variations, Colorado Assoc. Univ. Press, Boulder, p. 477.
Mestel, L. and Moss, D. L.: 1977,Monthly Notices Roy. Astron. Soc. 178, 27.
Mestel, L. and Spitzer, L.: 1956,Monthly Notices Roy. Astron. Soc. 116, 503.
Moss, D. L.: 1980,Astron. Astrophys. 91, 319.
Mullan, D. J.: 1974,Astrophys. J. 192, 149.
Novotny, E.: 1973,Introduction to Stellar Atmospheres and Interiors, Oxford Univ. Press, New York.
Parker, E. N.: 1975,Astrophys. J. 202, 523.
Piddington, J. H.: 1975,Astrophys. Space Sci. 34, 347.
Piddington, J. H.: 1976a, in V. Bumba and J. Kleczek (eds.), ‘Basic Mechanisms of Solar Activity’,IAU Symp. 71, 389.
Piddington, J. H.: 1976b,Astrophys. Space Sci. 41, 371.
Piddington, J. H.: 1977a,Astrophys. Space Sci. 47, 237.
Piddington, J. H.: 1977b,Astrophys. Space Sci. 47, 319.
Piddington, J. H.: 1979a,Astrophys. J. 233, 727.
Piddington, J. H.: 1979b,Aust. J. Phys. 32, 671.
Piddington, J. H.: 1981a,Astrophys. J. 247, 293.
Piddington, J. H.: 1981b,Cosmic Electrodynamics, Krieger, Malabar, Florida.
Piddington, J. H.: 1981c,Astrophys. Space Sci. 75, 273.
Piddington, J. H.: 1982,Astrophys. Space Sci. 87, 477.
Robinson, R. D., Worden, S. P., and Harvey, J. W.: 1980,Astrophys. J. 236, L155.
Schüssler, M. and Pähler, A.: 1978,Astron. Astrophys. 68, 57.
Simon, T., Linsky, J. L., and Stencel, R. E.: 1982,Astrophys. J., in press.
Stenflo, J. O.: 1976, in V. Bumba and J. Kleczek (eds.), ‘Basic Mechanisms of Solar Activity’,IAU Symp. 71, 69.
Stix, M.: 1981,Solar Phys. 74, 79.
Svalgaard, L., Duvall, T. L., and Scherrer, P. H.: 1978,Solar Phys. 59, 225.
Timothy, A. F., Krieger, A. S., and Vaiana, G. S.: 1975,Solar Phys. 42, 135.
Vaiana, G. S.: 1976,Phil. Trans. Roy. Soc. London A281, 365.
Vaiana, G. S., Cassinelli, J. P., and Fabbiano, G.: 1981,Astrophys. J. 245, 163.
Weiss, N. O.: 1966,Proc. Roy. Soc. London A293, 310.
Wilson, O. C.: 1978,Astrophys. J. 226, 379.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Piddington, J.H. On the origin and structure of stellar magnetic fields. Astrophys Space Sci 90, 217–230 (1983). https://doi.org/10.1007/BF00651562
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00651562