Cosmic ray time variations produced by deceleration in interplanetary space

1958 ◽  
Vol 8 (S2) ◽  
pp. 334-341 ◽  
Author(s):  
S. F. Singer
Keyword(s):  
Interplanetary Space ◽  
Cosmic Ray ◽  
Time Variations

Time variations of directional cosmic ray intensity at low latitudes - III. Interpretation of solar daily variation and changes of east-west asymmetry

1961 ◽  
Vol 263 (1312) ◽  
pp. 127-135 ◽  
Keyword(s):  
Energy Spectrum ◽  
Interplanetary Space ◽  
Daily Variation ◽  
Cosmic Ray ◽  
Local Source ◽  
Cosmic Ray Intensity ◽  
The Earth ◽  
Low Latitudes ◽  
Time Variations ◽  
East West

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.

Interplanetary and solar electrons of energy 3–12 MeV

1968 ◽  
Vol 46 (10) ◽  
pp. S761-S765 ◽  
Author(s):  
T. L. Cline ◽  
F. B. McDonald
Keyword(s):  
Interplanetary Space ◽  
Solar Physics ◽  
Strong Dependence ◽  
Cosmic Ray ◽  
High Energy ◽  
Solar Modulation ◽  
Relativistic Electrons ◽  
Time Histories ◽  
Electron Intensity ◽  
Time Variations

This paper reviews two topics related to the low-energy relativistic electrons detected in interplanetary space with the satellites IMP-I, IMP-II, and IMP-III:1. The first observations of 3–12-MeV solar-flare electrons in interplanetary space are presented. The solar electrons detected have kinetic energies nearly two orders of magnitude higher than any previously studied; thus, although flare events with a detectable flux of such particles occur relatively rarely, their study provides a new parameter in solar physics. The 7 July and 14 September 1966 events are outlined in detail, having the greatest relativistic electron to medium-energy proton ratios of the events detected before 1967. These events contrast with the 28 August 1966 event, which was intense in nucleons but contained no detectable component of relativistic electrons. The electron time histories are shown to have delayed onsets, and to be similar in form to those of high-energy protons, and the energy spectra and other features are described.2. Progress in the study of the solar modulation of interplanetary 3–12-MeV electrons is reviewed. Characteristics of the electron-intensity time variations during parts of 1963–67 are outlined; they are shown to be consistent with the hypothesis of the primary cosmic-ray nature of these particles and with a strong dependence on the local field conditions.

Time variations of the cosmic ray intensity in jamaica

1958 ◽  
Vol 3 (25) ◽  
pp. 55-62 ◽  
Author(s):  
J. C. Barton ◽  
J. H. Stockhausen
Keyword(s):  
Cosmic Ray ◽  
Cosmic Ray Intensity ◽  
Time Variations

Time variations of directional cosmic ray intensity at low latitude - II. Time variations of east-west asymmetry

1961 ◽  
Vol 263 (1312) ◽  
pp. 118-126 ◽  
Keyword(s):  
Geomagnetic Storms ◽  
Daily Variation ◽  
Cosmic Ray ◽  
Middle Latitude ◽  
Geomagnetic Disturbance ◽  
Equatorial Station ◽  
Cosmic Ray Intensity ◽  
Primary Cosmic Radiation ◽  
Time Variations ◽  
East West

Changes of the energy spectrum of primary cosmic radiation can be followed through the time variations of east-west asymmetry of the μ -meson component at low latitudes. Such a study has been conducted for the first time at Ahmedabad during 1957-8. The changes of east-west asymmetry are associated with changes of the daily variation of cosmic ray in­tensity, of the daily mean neutron intensity measured at equatorial and middle latitude stations, of the index of geomagnetic disturbance and of the horizontal component of the earth’s magnetic field. The study indicates that days with high east-west asymmetry are associated with geomagnetically quiet days and a cosmic ray daily variation consistent with its being produced by an anisotropy of primary radiation outside the influence of the geomagnetic field. On such days, the daily variation produced by the anisotropy, as observed at an equatorial station, has a significant diurnal as well as a semi-diurnal component. High east-west asymmetry and associated anisotropy occur 3 to 5 days before the arrival of solar corpuscular beams which envelop the earth. Days with low east-west asymmetry occur about 3 to 4 days after the onset of cosmic ray storms associated with geomagnetic storms, usually of the SC type.

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