Abstract
Magnetic fields in the low corona are the only plausible source of energy for solar flares. Other energy sources appear inadequate or uncorrelated with flares. Low coronal magnetic fields cannot be measured accurately, so most attention has been directed toward measurements of the photospheric magnetic fields from which coronal developments may be inferred. Observations of these magnetic fields are reviewed. It is concluded that, except possibly for the largest flares, changes in the photospheric magnetic fields in flaring centers are confined to evolutionary changes associated with emergence of new magnetic flux. Flare observations with the 10830 Å line of helium, in particular, are discussed. It is concluded that the brightest flare knots appear near points of emergent magnetic flux. Pre-flare activation and eruptions of Hα filaments are discussed. It is concluded that the rapid motions in filaments indicate unambiguously that the magnetic fields in the low corona are severely disrupted prior to most flares. The coronal signature of Hα filament eruptions is illustrated with soft X-ray photographs from the S-054 experiment of the NASA Skylab mission. An attempt is made, by studying X-ray flare morphology, to determine whether flares grow by reconnections between adjacent or intertwined magnetic elements or by triggering, in which each flaring loop drives adjacent loops to unstable states. It is concluded that successive loop brightenings are most easily interpreted as the result of magnetic field reconnections, although better time resolution is required to settle the question. A model of magnetic field reconnections for flares associated with filament activation and emerging magnetic flux is presented.
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Brueckner, G. E.: 1976, Phil. Trans. Roy. Soc. Lond. A281, 443.
Bruzek, A.: 1975, Solar Phys. 42, 215.
Canfield, R. C., Priest, E. R., and Rust, D. M.: 1974, in Y. Nakagawa and D. M. Rust (eds.), Flare Related Magnetic Field Dynamics, Natl. Ctr. Atmos. Res., Boulder, Colo., p. 361.
Cowling, T. G.: 1946, Monthly Notices Royal Astron. Soc. 106, 218.
Elliot, H.: 1974, in R. Ramaty and R. G. Stone (eds.), High Energy Phenomena on the Sun, NASA SP-342, Washington, D.C., p. 12.
Foukal, P.: 1970, Solar Phys. 13, 330.
Frazier, E. N.: 1972, Solar Phys. 26, 130.
Giovanelli, R. G.: 1939, Astrophys. J. 89, 555.
Golub, L., Krieger, A. S. Silk, J. K., Timothy, A. F., and Vaiana, G. S.: 1974, Astrophys. J. Letters 189, 93.
Harvey, K. L. Livingston, W. D., Harvey, J. W., and Slaughter, C. D.: 1971, IAU Symp. 43, 422.
Harvey, K. L., Harvey, J. W., and Martin, S. F.: 1975, Solar Phys. 40, 87.
Howard, R. and Babcock, H. W.: 1960, Astrophys. J. 132, 218.
Kahler, S. W., Krieger, A. S., and Vaiana, G. S.: 1975, Astrophys. J. Letters 199, 57.
Kiepenheuer, K. O.: 1963, in W. N. Hess (ed.), The Physics of Solar Flares, NASA SP-50, Washington, D.C., p. 323.
Koval, A. N. and Stepanyan, N. N.: 1972, Solar Data No. 1, 83.
Kuperus, M. and Raadu, M. A.: 1974, Astron. Astrophys. 31, 189.
Livingston, W. C.: 1974, in Y. Nakagawa and D. M. Rust (eds.), Flare Related Magnetic Field Dynamics, Natl. Ctr. Atmos. Res., Boulder, Colo, p. 269.
Martin, S. F. and Ramsey, H. E.: 1972, in P. S. McIntosh and M. Dryer (eds.), Solar Activity Observations and Predictions, M.I.T. Press, Cambridge, Mass., p. 371.
Martres, M. J., Michard, R., and Soru-Iscovici, I.: 1966, Ann. Astrophys. 29, 249.
Martres, M. J., Michard, R., Soru-Iscovici, I., and Tsap, T. T.: 1968, Solar Phys. 5, 187.
Michalitsanos, A. G. and Kupferman, P.: 1974, Solar Phys. 36, 403.
Moreton, G. E. and Severnyi, A. B.: 1968, Solar Phys. 3, 282.
Neupert, W. M., Thomas, R. J., and Chapman, R. D.: 1974, Solar Phys. 34, 349.
Ogir, M. B.: 1971, Izv. Krymsk. Astrofiz. Obs. 43, 165.
Ogir, M. B. and Shaposhnikova, E. F.: 1965, Izv. Krymsk. Astrofiz. Obs. 34, 272.
Pallavicini, R., Vaiana, G. S., Kahler, S. W., and Krieger, A. S.: 1975, Solar Phys. 75, 411.
Petrasso, R. D., Kahler, S. W., Krieger, A. S., Silk, J. K., and Vaiana, G. S.: 1975, Astrophys. J. Letters 199, 127.
Priest, E. R. and Sonnerup, B. U. O.: 1975, Geophys. J. Roy. Astron. Soc. 41, 405.
Ramsey, H. and Martin, S. F.: 1974, Lockheed Contract Report LMSC/D401258, Lockheed Missiles & Space C., Burbank, Calif.
Ribes, E.: 1969, Astron. Astrophys. 2, 316.
Rompolt, B.: 1975, Rotational Motions in Fine Solar Structures, Acta Universitatis Wratisloviensis No. 252, Warsaw.
Roy, J.-R.: 1973, Solar Phys. 28, 95.
Roy, J.-R. and Tang, F.: 1975, Solar Phys. 42, 425.
Rust, D. M.: 1968, IAU Symp. 35, 77.
Rust, D. M.: 1972, Solar Phys. 25, 141.
Rust, D. M.: 1973, Solar Phys. 33, 205.
Rust, D. M.: 1976, Phil. Trans. Roy. Soc. Lond. A281, 427.
Rust, D. M. and Bar, V.: 1973, Solar Phys. 33, 445.
Rust, D. M. and Bar, V.: 1973, Solar Phys. 33, 445.
Rust, D. M. and Bridges, C. A.: 1975, Solar Phys. 43, 129.
Rust, D. M., Nakagawa, Y., and Neupert, W. M.: 1975, Solar Phys. 41, 397.
Severnyi, A. B.: 1963, Soviet Astron.-AJ 6, 747.
Severnyi, A. B.: 1969, Anals IQSY 3, 11.
Sonnerup, B. U. O.: 1972, in R. Ramaty and R. G. Stone (eds.), High Energy Phenomena on the Sun, NASA SP-342, Washington, D.C., p. 357.
Švestka, Z.: 1976, Solar Flares, D. Reidel Publ. Co., Dordrecht, Holland.
Tanaka, K.: 1975, Bull. Am. Astron. Soc. 7, A423.
Tanaka, K. and Nakagawa, Y.: 1973, Solar Phys. 33, 187.
Tandberg-Hanssen, E.: 1974, Solar Prominences, D. Reidel Publ. Co., Dordrecht, Holland.
Thomas, R. J.: 1975, IAU Symp. 68, 25.
Thomas, R. J. and Teske, R. G.: 1971, Solar Phys. 16, 431.
Vaiana, G. S., Krieger, A. S., and Timothy, A. F.: 1973, Solar Phys. 32, 81.
Vorpahl, J. A., Gibson, E. G., Landecker, P. B., McKenzie, D. L. and Underwood, J. H.: 1975, Solar Phys. (in press).
Webb, D., Krieger, A. S., and Rust, D. M.: 1976, Solar Phys. (in press).
Widing, K. G.: 1975, IAU Symp. 68, 153.
Widing, K. G. and Cheng, C. C.: 1975, Astrophys. J. Letters 194, 111.
Wiehr, E.: 1972, Solar Phys. 24, 129.
Zirin, H.: 1974, Vistas Astron. 16, 1.
Zirin, H. and Tanaka, K.: 1973, Solar Phys. 32, 173.
Zvereva, A. M. and Severnyi, A. B.: 1970, Izv. Krymsk. Astrofiz. Obs. 41–42, 97.
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Rust, D.M. An active role for magnetic fields in solar flares. Sol Phys 47, 21–40 (1976). https://doi.org/10.1007/BF00152243
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DOI: https://doi.org/10.1007/BF00152243