Satellite measurements of the low-energy cosmic-ray Li, Be, B, C, N, O, F nuclei and their implications

1968 ◽  
Vol 46 (10) ◽  
pp. S548-S552 ◽  
Author(s):  
C. Y. Fan ◽  
George Gloeckler ◽  
J. A. Simpson

The differential energy spectrum and chemical abundance of individual elements from lithium to fluorine have been measured near minimum solar modulation (June 1965 to March 1966) in interplanetary space on the IMP-III satellite. The spectra for Li, Be, and B are found to increase with decreasing energy below ~60 MeV/nucleon. The consequences of these results on the propagation and lifetimes of cosmic-ray particles are discussed.

Space Weather ◽  
2016 ◽  
Vol 14 (3) ◽  
pp. 247-258 ◽  
Author(s):  
C. Zeitlin ◽  
A. W. Case ◽  
N. A. Schwadron ◽  
H. E. Spence ◽  
J. E. Mazur ◽  
...  

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.


2019 ◽  
Vol 210 ◽  
pp. 01003
Author(s):  
V. Prosin ◽  
I. Astapov ◽  
P. Bezyazeekov ◽  
A. Borodin ◽  
M. Brückner ◽  
...  

The extensive air shower Cherenkov light array Tunka-133 collected data during 7 winter seasons from 2009 to 2017. From 2175 hours of data taking, we derived the differential energy spectrum of cosmic rays in the energy range 6 · 1015 2 · 1018 eV. The TAIGA-HiSCORE array is in the process of continuous expansion and modernization. Here we present the results obtained with 28 stations of the first HiSCORE stage from 35 clear moonless nights in the winter of 2017-2018. The combined spectrum of two arrays covers a range of 2 · 1014 – 2 · 1018 eV.


1982 ◽  
Vol 32 (10) ◽  
pp. 1183-1186
Author(s):  
S. R. Ganguly ◽  
Banashree Mitra ◽  
S. D. Chatterjee

1968 ◽  
Vol 46 (10) ◽  
pp. S598-S600
Author(s):  
E. Tamai ◽  
M. Tsubomatsu ◽  
K. Ogura

Nuclear emulsions were exposed at 2.3 g cm−2 atmospheric depth over Fort Churchill in 1965. These emulsions have been examined for the tracks of multiply-charged [Formula: see text] nuclei, with emphasis being paid particularly to those particles that stopped in the emulsions. Differential energy spectra of α particles and [Formula: see text], [Formula: see text]and [Formula: see text] nuclei were obtained in the energy interval 60–550 MeV/nucleon. They represent experimental results during the period when solar modulation effects were at a minimum. The fluxes of α particles and L, M, and H nuclei for energy intervals of 60–170, 100–400, 100–525, and 140–550 MeV/nucleon were found to be 20.9 ± 1.2, 2.4 ± 0.4, 4.8 ± 0.6, and 2.5 ± 0.4 particles m−2 sr−1 s−1, respectively. The results also show that the L/M and H/M ratios at the top of the atmosphere were 0.56 ± 0.16 and 0.34 ± 0.13 respectively, in the energy range from 140 to 350 MeV/nucleon. These values are appreciably greater than those observed at higher energies.


1968 ◽  
Vol 46 (10) ◽  
pp. S761-S765 ◽  
Author(s):  
T. L. Cline ◽  
F. B. McDonald

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.


1971 ◽  
Vol 49 (1) ◽  
pp. 34-48 ◽  
Author(s):  
G. Subramanian

The semidiurnal variation of galactic cosmic ray intensity is investigated using data from mainly high counting rate neutron and meson monitors during 1964–1968. It is shown that in order to explain the observed semidiurnal variation it is necessary that an anisotropy of cosmic ray intensity be present in interplanetary space. The energy spectrum and the asymptotic latitude dependence of the anisotropy are then determined. The energy spectrum has a positive exponent close to + 1 for the power law in energy. The strength of the anisotropy decreases more rapidly than cosλ with increasing asymptotic latitude λ, both cos2λ and cos3λ being acceptable. The distribution of cosmic ray intensity in the range of heliolatitudes ± 7.25° at the orbit of the earth, obtained using data from the Ottawa neutron monitor, does not support the explanation of the semidiurnal variation based on the models of Subramanian and Sarabhai or Lietti and Quenby.


1997 ◽  
Vol 480 (1) ◽  
pp. 371-376 ◽  
Author(s):  
A. W. Labrador ◽  
R. A. Mewaldt

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