scholarly journals On the Increase in Cosmic Ray Intensity and the Electromagnetic State in Interplanetary Space during the Solar Flare of Feb. 23, 1956

Tellus ◽  
1958 ◽  
Vol 10 (1) ◽  
pp. 126-136 ◽  
Author(s):  
Dieter Eckhartt
1958 ◽  
Vol 6 ◽  
pp. 355-376
Author(s):  
J. A. Simpson

The principal characteristics for changes of cosmic ray intensity as a function of time and primary particle energy are reviewed for those intensity variations which are thought to be of non-terrestrial origin. These variations are either (a) temporary increases of cosmic ray intensity arising from thede novoproduction of cosmic ray particles in the vicinity of the sun in association with some solar flares, or (b) the modulation of extra-solar cosmic radiation within the interplanetary volume by a modulation mechanism related to solar activity.The study of these variations for low-energy cosmic ray particles is also a unique tool for the investigation of interplanetary magnetic fields and other properties of interplanetary space. As an example, the cosmic ray events associated with the giant solar flare of 23 February 1956 have been studied. The experimental evidence shows that interplanetary magnetic fields must exist for the storage and redistribution of the solar flare cosmic ray particles. A more specific model indicates that disordered magnetic fields lie mainly beyond the orbit of the earth and that diffusion through these irregular magnetic fields is the prominent mechanism for particle storage. In addition, this cosmic ray intensity increase was fortunately superposed in such a way upon a change of intensity arising from a modulation mechanism that it is possible to restrict the kinds of models which account for modulation of cosmic ray intensity within the interplanetary volume.


1956 ◽  
Vol 3 (5) ◽  
pp. 1153-1155 ◽  
Author(s):  
F. Bachelet ◽  
A. M. Conforto

Nature ◽  
1960 ◽  
Vol 186 (4721) ◽  
pp. 299-300 ◽  
Author(s):  
H. ELLIOT

The daily variation of cosmic ray intensity at low latitudes can under certain conditions be associated with an anisotropy of primary radiation. During 1957-8, this anisotropy had an energy spectrum of variation of the form aϵ -0.8±0.3 and corresponded to a source situated at an angle of 112 ± 10° to the left of the earth-sun line. The daily variation which can be associated with a local source situated along the earth-sun line has an energy spectrum of variation of the form aϵ 0 . Increases in east-west asymmetry and the associated daily variation for east and west directions can be explained by the acceleration of cosmic ray particles crossing beams of solar plasma in the neighbourhood of the earth. For beams of width 5 x 10 12 cm with a frozen magnetic field of the order of 10 -4 G, a radial velocity of about 1.5 x 108 cm/s is required. The process is possible only if the ejection of beams takes place in rarefied regions of inter­ planetary space which extend radially over active solar regions. An explanation of Forbush, type decreases observed at great distances from the earth requires similar limitation on the plasma density and conductivity of regions of interplanetary space. The decrease of east-west asymmetry associated with world-wide decreases of intensity and with SC magnetic storms is consistent with a screening of the low-energy cosmic ray particles due to magnetic fields in plasma clouds.


1958 ◽  
Vol 6 ◽  
pp. 377-385
Author(s):  
V. Sarabhai ◽  
N. W. Nerurkar ◽  
S. P. Duggal ◽  
T. S. G. Sastry

Study of the anisotropy of cosmic rays from the measurement of the daily variation of meson intensity has demonstrated that there are significant day-today changes in the anisotropy of the radiation. New experimental data pertaining to these changes and their solar and terrestrial relationships are discussed.An interpretation of these changes of anisotropy in terms of the modulation of cosmic rays by streams of matter emitted by the sun is given. In particular, an explanation for the existence of the recently discovered types of daily variations exhibiting day and night maxima respectively, can be found by an extension of some ideas of Alfvén, Nagashima, and Davies. An integrated attempt is made to interpret the known features of the variation of cosmic ray intensity in conformity with ideas developed above.


1980 ◽  
Vol 91 ◽  
pp. 393-398
Author(s):  
A. Geranios

Observations of cosmic ray intensity depressions by earth bound neutron monitors and measurements of interplanetary parameter's variations aboard geocentric satellites in the period January 1972-July 1974 are analysed and grouped according to their correlation among them. From this analysis of about 30 cases it came out that the majority of the depressions correlates with the average propagation speed of interplanetary shocks as well as with the amplitude of the interplanetary magnetic field after the eruption of a solar flare. About one fourth of the events correlates with corotating fast solar wind streams. As the recovery time of the shock-related depressions depends strongly on the heliographic longitude of the causitive solar flare, it seems that the cosmic ray modulation region has a corotative-like feature.


1968 ◽  
Vol 1 (4) ◽  
pp. 148-149
Author(s):  
B. J. Stone

This paper is a progress report on an examination of the short-term variability of solar proton flux in interplanetary space at times of solar flare activity. The data are from the GRCSW cosmic-ray detector on board the Pioneer 7 space probe, which, at the times to be discussed, was more than a million miles from the Earth.


Physica ◽  
1956 ◽  
Vol 22 (1-5) ◽  
pp. 355-356 ◽  
Author(s):  
M.A. Assies ◽  
H.F. Jongen

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