ISSN:
1573-093X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract On September 29, 1968 a proton event has been recorded during three balloon flights performed at Reykjavik, Iceland (64.2 N, 21.7 W) with GM telescopes and scintillation detector. Solar X-rays have been recorded at 1620 UT when a flare of Importance 2B occurred at N 16, W 52. A comparison between X-rays and microwave emissions is made; the time of the maximum of X-ray intensity is taken as the time of the acceleration and ejection of the particles. The beginning of the proton event is at 1650 UT, and particles were observed for almost 24 h. The spectrum of solar protons E〉120 MeV is given for several periods between 7 and 20 h after the flare using three independent methods. The solar particle source spectrum is found as: 321-01 (particles/MeV ster), which implies that (1.2±0.1) × 1031 protons (E〉120 MeV)/ster have been ejected by the Sun. The time behaviour of the event fits well with Krimigis' model for solar particles diffusion in the interplanetary space. Comparison with other events shows that the radial dependence of the diffusion coefficient is the same (β≈1) on September 28, 1961, July 7, 1966 and September 29, 1968. The diffusion mean free path at 1 AU is 0.11 AU for 1966, period of low solar activity, and decreases with solar activity (0.08 AU for 1961 and 1968). The fit of the time behaviour of the event with Burlaga's ADB model is also discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00145947
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