Abstract
Particle acceleration during solar flares is a complex process where the main ‘actors’ (Direct (D.C.) or turbulent electric fields) are hidden from us. It is easy to construct a successful particle accelertion model if we are allowed to impose on the flaring region arbitrary conditions (e.g., strength and scale length of the D.C. or turbulent electric fields), but then we have not solved the acceleration problem; we have simply re-defined it. We outline in this review three recent observations which indicate that the following physical processes may happen during solar flares: (1) Release of energy in a large number of microflares; (2) short time-scales; (3) small length scales; and (4) coherent radiation and acceleration sources. We propose that these new findings force us to reformulate the acceleration process inside a flaring active region assuming that a large number of reconnection sites will burst almost simultaneously. All the well-known acceleration mechanisms (electric fields, turbulent fields, shock waves, etc.) reviewed briefly here, can be used in a statistical model where each particle is gaining energy through its interaction with many small reconnection sites.
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References
Alfvén, H. and Carlqvist, P.: 1967, Solar Phys. 1, 220.
Ambrosiano, J. J. Matthaeus, D., Goldstein, M. L., and Plante, D. R.: 1989, J. Geophys. Res. (in press).
Benz, A. O.: 1985, Solar Phys. 96, 357.
Benz, A. O. and Smith, D.: 1987, Solar Phys. 107, 299.
Benz, A. O., Zlobec, P., and Jaeggi, M.: 1982, Astron. Astrophys. 109, 305.
Benz, A. O., Ashwanden, M. J., and Wiehl, J. J.: 1984, Decimetric Radio Emission During Solar Flares, Kunming Workshop Proceedings.
Block, L. P.: 1978, Astrophys. Space Sci. 55, 59.
Buchner, J. and Zeleny, L. M.: 1986, Proceedings of the Joint Varena-Abastumani International school and Workshop on ‘Plasma Astrophysics’, ESA SP-251, p. 195.
Bulanov, S. V.: 1986, Proceedings of the Joint Varena-Abastumani International School and Workshop on ‘Plasma Astrophysics’, ESA SP-251, p. 185.
Cargill, P. J.: 1989, J. Geophys. Res. (submitted).
Cargill, P. J. and Goodrich, C. C: 1987, Phys. Fluids 30, 2504.
Cargill, P. J., Goodrich, C. C., and Vlahos, L.: 1988, Astron. Astrophys. 189, 254.
Chupp, E. L.: 1984, Ann. Rev. Astron. Astrophys. 22, 359.
Datlowe, D. W., Elcan, M. J., and Hudson, H. S.: 1974, Solar Phys. 39, 127.
Decker, R. B.: 1989, Space Sci Rev. (in press).
Decker, R. D. and Vlahos, L.: 1986, Astrophys. J. 306, 710.
De Jager, C.: 1986, Space Sci. Rev. 44, 43.
De Jager and De Jonge, G.: 1978, Solar Phys. 58, 127.
Droge, F.: 1977, Astron. Astrophys. 57, 285.
Forrest, D. J. and Chupp, E. L.: 1983, Nature 305, 291.
Forman, M. A., Ramaty, R., and Zweibel, E. G.: 1985, in P. A. Sturrock (ed.), The Physics of the Sun, D. Reidel Publ. Co., Dordrecht, Holland, p. 249.
Heyvaerts, J.: 1981, in E. R. Priest (ed.), ‘Particle Acceleration in Solar Flares’, Solar Flare Magnetohydrodynamics, Gordon and Breach, New York, p. 429.
Holman, G.: 1985, Astrophys. J. 293, 584.
Holman, G., Kundu, M. R., and Eichler: 1983, in M. R. Kundu and T. E. Gergely (eds.), ‘Radio Physics of the Sun’, IAU Symp. 86, 457.
Hubbard, R. F. and Joyce, C.: 1979, J. Geophys. Res. 84, 4297.
Karimabadi, H., Menyuk, C. R., Sprangle, P., and Vlahos, L.: 1987, Astrophys. J. 316, 462.
Kolomenskii, A. A. and Lebedev, A. N.: 1963, Soviet Phys. Dokl. 7, 745.
Kaufmann, P. et al.: 1985, Solar Phys. 95, 155.
Lampe, M. and Papadopoulos, K.: 1977, Astrophys. J. 212, 886.
Lin, R. P., Schwartz, R. A., Kane, S. R., Pelling, R. M., and Harley, K. C.: 1983, Astrophys. J. 251, L109.
Low, B. C. and Wolfson, R.: 1988, Astrophys. J. 324, 574.
Martin, R. F.: 1986, J. Geophys. Res. 91, 11985.
Melrose, D. B.: 1983, Solar Phys. 89, 149.
Melrose, D. B. and Dulk, G. A.: 1982, Astrophys. J. 259, 844.
Moffat, H. K., 1987, in G. Comte-Bellot and J. Mathieu (eds.), Advances in Turbulence, Springer-Verlag, p. 240.
Moghaddam-Taaheri, E. and Vlahos, L.: 1987, Phys. Fluids 30, 3155.
Moghaddam-Taaheri, E., Vlahos, L., Rowland, H. L., and Papadopoulos, K.: 1985, Phys. Fluids 28, 3034.
Parker, E.: 1972, Astrophys. J. 174, 499.
Parker, E.: 1988, Astrophys. J. 330, 474.
Ramaty, R and Murphy, R. J.: 1987, Space Sci. Rev. 45, 213.
Roberts, C. S. and Buchsbaum, S. J.: 1964, Phys. Rev. A135, 381.
Sakai, Y. and Ohsawa, J.: 1987, Space Sci. Rev. 46, 113.
Sharma, R. R., Vlahos, L., and Papadopoulos, K.: 1982, Astron. Astrophys. 112, 377.
Scholer, M.: 1988, in O. Havnes et al. (eds.), Activity in Cool Star Envelopes, D. Reidel Publ. Co., Dordrecht, Holland, p. 195.
Slottje, C.: 1978, Nature 275, 520.
Smith, D. F.: 1980, Solar Phys. 66, 135.
Smith, R., 1983, in M. R. Kundu and G. Holman (eds.), ‘Unstable Current Systems and Instabilities in Astrophysics’, IAU Symp. 107, 113.
Spicer, D. S.: 1983, Adv. Space Res. 2, 135.
Sprangle and Vlahos, L.: 1983, Astrophys. J. 273, L95.
Steinolfson, R. S. and Van Hoven, G.: 1984, Astrophys. J. 276, 391.
Toptyghin, I. N.: 1980, Space Sci Rev. 26, 157.
Tverskoi, B. A.: 1967, Soviet Phys. JEPT 25, 317.
Van Hoven, G.: 1979, Astrophys. J. 232, 572.
Van Hoven, G, Tachi, T., and Steinolfson, R. S.: 1984, Astrophys. J. 280, 391.
Vlahos, L., Sharma, R. R., and Papadopoulos, K.: 1983, Astrophys. J. 275, 374.
Vlahos, L. et al.: 1986, Energetic Phenomena on the Sun, NASA CP-2439, p. 2–1.
Winglee, R. M., Pritchett, P. L., and Dulk, G. A.: 1988, Astrophys. J. 327, 968.
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Vlahos, L. Particle acceleration in solar flares. Sol Phys 121, 431–447 (1989). https://doi.org/10.1007/BF00161711
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DOI: https://doi.org/10.1007/BF00161711