Abstract
328 particle events recorded during 30 months from January 1, 1966 to June 30, 1968 (taken from the new Catalog of Solar Particle Events, 1955–1969) are compared with the occurrence of 166 type II radio bursts during the same period. The results of this comparison give a convincing evidence that proton acceleration to higher energies in flares (the ‘second acceleration step’) is closely connected with the type II burst occurrence. The shock wave appears to originate near the time when the impulsive burst occurs, and the second acceleration step follows immediately the first one; in some cases the second step sets in while the first step is still in progress.
A detailed analysis indicates that we may need even three different acceleration mechanisms in flares: The first one gives rise to electrons which produce the microwave and hard X-ray bursts (and it probably also accelerates protons to low energies); the second, which sometimes coincides (but mostly does not coincide) with the first one, produces beams of electrons which give rise to type III bursts; and the third one, characterized by the type II burst-producing shock wave, accelerates (on some, rather rare occasions) the particles, preaccelerated by the first mechanism, to higher energies.
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References
Catalog of Solar Particle Events, 1955–1969: 1974, to be published in the series ‘Astrophysics and Space Science Library’, D. Reidel, Dordrecht (ed. by Z. Švestka and P. Simon).
Chupp, E. L.: 1973, ‘Gamma Ray and Neutron Measurements and Their Relation to the Solar Flare Problem’, Space Res. 14, in press.
de Jager, C.: 1969, in C. de Jager and Z. Švestka (eds.), ‘Solar Flares and Space Research’, COSPAR Symp., p. 1.
Dodson, H. W. and Hedeman, E. R.: 1969, Solar Phys. 9, 278.
Frost, K. J.: 1969, Astrophys. J. 158, L159.
Frost, K. J. and Dennis, B. R.: 1971, Astrophys. J. 165, 655.
Kane, S. R.: 1972, Solar Phys. 27, 174.
Lockwood, J. A.: 1968, J. Geophys. Res. 73, 4247.
Maxwell, A. and Thompson, A. R.: 1962, Astrophys. J. 135, 138.
Quarterly Bulletin on Solar Activity: 1958, ed. by M. Waldmeier, Eidgenössische Sternwarte Zürich.
Quarterly Bulletin on Solar Activity: 1966–1968, ed. by M. Waldmeier, Eidgenössische Sternwarte Zürich.
Roberts, J. A.: 1959, Australian J. Phys. 12, 327.
Slottje, C.: 1973, private communication.
Smart, D. F. and Shea, M. A.: 1971, Solar Phys. 16, 484.
Smerd, S. F., Wild, J. P., and Sheridan, K. V.: 1962, Australian J. Phys. 15, 180.
Solar-Geophysical Data: 1966–1968, ed. by H. I. Leighton under the supervision of D. B. Bucknam and J. V. Lincoln, NOAA Environmental Data Service, Boulder.
Sturrock, P. A.: 1968, in K. O. Kiepenheuer (ed.), ‘Structure and Development of Solar Active Regions’, IAU Symp. 35, 471.
Švestka, Z.: 1970, Solar Phys. 13, 471.
Švestka, Z.: 1974, Solar Flares, D. Reidel Publ. Co., Dordrecht, Holland, in press.
Švestka, Z. and Olmr, J.: 1966, Bull. Astron. Inst. Czech. 17, 4.
Wild, J. P., Smerd, S. F., and Weiss, A. A.: 1963, Ann. Rev. Astron. Astrophys. 1, 291.
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Mitteilungen aus dem Fraunhofer Institut Nr. 125.
Grant of Stifterverband für die Deutsche Wissenschaft.
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Švestka, Z., Fritzová-Švestková, L. Type II radio bursts and particle acceleration. Sol Phys 36, 417–431 (1974). https://doi.org/10.1007/BF00151211
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DOI: https://doi.org/10.1007/BF00151211