Abstract
The effect of Coulomb losses on the stochastic acceleration of high energy electrons in solar flares is investigated. Including Coulomb losses makes the acceleration less efficient at low energies, the resulting particle spectra show a steepening below an energy Ec, typically 1 – 3 MeV, where the loss rate equals the acceleration rate. It is shown that electrons can efficiently be accelerated to high energies even if they are injected at energies E < Ec. The solutions successfully explain the observed steepening of interplanetary electron spectra below ≈ 3 MeV following impulsive solar flares taking place at low coronal heights. It is concluded that simultaneous second-order Fermi acceleration and Coulomb losses operating in closed flare loops are a likely mechanism for second-step acceleration in impulsive solar flares.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
Similar content being viewed by others
References
Abramowitz.M., and Stegun, I.A., 1965, Handbook of Mathematical Functions (New York: Dover)
Bai, T., 1982, Ap.J., 259, 342
Bai, T., Hudson, H.S., Pelling, R.M., Lin, R.P., Schwartz, R.A., and von Rosenvinge, T.T., 1983, Ap.J., 267, 433
Bai, T., 1986, Ap.J., 308, 912
Barbosa, D.D 1979, Ap.J., 233, 383
Cane, H.V., McGuire, R.E., and von Rosenvinge, T.T., 1986, Ap.J. 301, 448
Canfield, R.C, Priest, E.R., and Rust, D.M., 1974, in: Flare-related Magnetic Field Dynamics (ed. Nakagawa, Y., and Rust, D.M.) NC AR, Boulder
Chupp, E.L., 1984, Ann. Rev. Astr. Ap., 22, 359.
deJager, C, 1969, in: Cospar Symp. on Solar Flares and Space Research (deJager, C, and Zvestka, Z., editors) p. 1
Dröge, W., and Schlickeiser, R., 1986, Ap.J. 305, 909
Dröge, W., Lerche, I., and Schlickeiser, R., 1987, Astr.Ap., 178, 252
Ellison, D.C, and Ramaty, R., 1985, Ap.J., 298, 400
Evenson, P., Meyer, P., Yanagita, S., and Forrest, D., 1984, Ap.J. 283, 439
Evenson, P., Hovestadt, D., Meyer, P., and Moses, D.,1985, Proc. 19th Internat. Cosmic Ray Conf. 3, 74
Fermi, E., 1949, Phys. Rev. 75, 1169.
Forman, M.A, Ramaty, R., and Zweibel, E.G., 1985, in: The Physics of the Sun, ed. Sturrock, P.A. (Dordrecht:Reidel) Vol II, p. 249
Forrest, D.J., et al., 1981, Proc. 17th Internat. Cosmic Ray Conf. 10, 5
Ginzburg, V.L., and Syrovatskii, S.I., 1964, The Origin of Cosmic Rays, (Oxford, Pergamon).
Heyvaerts, J., Priest, E.R., and Rust, D.M., 1977, Ap.J., 216, 123
Kane, S.R., Chupp, E.L., Forrest, D.J., Share, G.H., and Rieger, E., Ap.J. 300, L95
Lagage, P.O., and Cesarsky, C.J., 1983, Astr. Ap., 118, 223.
Lin, R.P., Mewaldt, R.A., and van Hollebeke, M.A.I., 1982, Ap.J., 253, 949
McGuire, R.E., and von Rosenvinge, T.T., 1984, Adv. Space Res., 4, 117.
Pallavicini, R., Serio, S., and Vaiana, G., 1977, Ap.J., 216, 108
Parker, E.N., and Tidman, D.A., 1958, Phys. Rev. 111, 1206.
Ramaty, R., 1979, in: Particle Acceleration Mechanisms in Astrophysics, ed. J. Arons, CMax, and CMcKee (AIP, No.56; NewYork:AIP), p. 135
Ramaty, R. et al., 1980, in: Solar Flares, ed. P.A.Sturrock, Colorado Assoc. Univ. Press, Boulder, p. 117.
Steinacker, J., Dröge, W., Schlickeiser, R., 1988, Solar Phys. (in press).
Wild, J.P., Smerd, S.F., and Weiss, A.A., 1963, Ann. Rev. Astr. Ap. 1, 291.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1989 Kluwer Academic Publishers
About this chapter
Cite this chapter
Dröge, W. (1989). Electron Acceleration in Impulsive Solar Flares. In: Shapiro, M.M., Wefel, J.P. (eds) Cosmic Gamma Rays, Neutrinos, and Related Astrophysics. NATO ASI Series, vol 270. Springer, Dordrecht. https://doi.org/10.1007/978-94-009-0921-2_38
Download citation
DOI: https://doi.org/10.1007/978-94-009-0921-2_38
Publisher Name: Springer, Dordrecht
Print ISBN: 978-94-010-6903-8
Online ISBN: 978-94-009-0921-2
eBook Packages: Springer Book Archive