A high-energy increase in cosmic-ray intensity

1991 ◽  
Vol 69 (8-9) ◽  
pp. 984-987
Author(s):  
D. Venkatesan ◽  
A. G. Ananth
Keyword(s):  
Solar Flare ◽  
Cosmic Ray ◽  
High Energy ◽  
Energy Increase ◽  
Neutron Monitors ◽  
Geomagnetic Index ◽  
Cosmic Ray Intensity ◽  
Energy Cutoff ◽  
High Energy Phenomenon ◽  
Interplanetary Disturbance

The increase in cosmic rays observed by neutron monitors with high-energy cutoff, on April 29, 1973, is interpreted to be a definite high-energy phenomenon. This is not associated with any solar flare or interplanetary disturbance. The association of the increase in intensity with geomagnetic index Dst variation indicates a possibility that the high-energy event was caused by a magnetospheric phenomenon.

scholarly journals Variations of Interplanetary Parameters and Cosmic-Ray Intensities

1980 ◽  
Vol 91 ◽  
pp. 393-398
Author(s):  
A. Geranios
Keyword(s):  
Solar Flare ◽  
Recovery Time ◽  
Propagation Speed ◽  
Cosmic Ray ◽  
Interplanetary Shocks ◽  
Fast Solar Wind ◽  
Neutron Monitors ◽  
Cosmic Ray Intensity ◽  
Cosmic Ray Modulation ◽  
Modulation Region

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.

Ulysses Out-of-Ecliptic Observations of “27-Day” Variations in High Energy Cosmic Ray Intensity

1995 ◽  
pp. 403-408 ◽  
Author(s):  
R. B. Mckibben ◽  
J. A. Simpson ◽  
M. Zhang ◽  
S. Bame ◽  
A. Balogh
Keyword(s):  
Cosmic Ray ◽  
High Energy ◽  
Cosmic Ray Intensity

Increase of cosmic ray intensity associated with the solar flare of February 23, 1956

1956 ◽  
Vol 3 (5) ◽  
pp. 1153-1155 ◽  
Author(s):  
F. Bachelet ◽  
A. M. Conforto
Keyword(s):  
Solar Flare ◽  
Cosmic Ray ◽  
Cosmic Ray Intensity

Daily variation of cosmic rays during quiet and disturbed periods in 1965 and 1966

1968 ◽  
Vol 46 (10) ◽  
pp. S819-S822
Author(s):  
Pekka J. Tanskanen
Keyword(s):  
Daily Variation ◽  
Cosmic Ray ◽  
Ecliptic Plane ◽  
Neutron Monitors ◽  
Monthly Basis ◽  
Cosmic Ray Intensity ◽  
Variable Amplitude ◽  
Ecliptic Latitude ◽  
Streaming Velocity ◽  
Corrected Data

Data from super neutron monitors at Deep River, Churchill, Resolute, and Alert have been used to study the daily variation of cosmic-ray intensity during 1965 and 1966. Intensities have been examined on a daily, weekly, and monthly basis as a function of the asymptotic direction of vertically incident 7.5-BeV particles. The data have been analyzed in an earth-centered solar-ecliptic coordinate system in which daily (due to the earth's rotation) and seasonal (due to the inclination of the earth's axis to the ecliptic plane) variations of the asymptotic directions are considered.During undisturbed periods the daily variation has been examined by applying a digital filter to the pressure-corrected data and also to the data after subtraction of a variable-amplitude Parker–Axford theoretical diurnal variation. Particular attention has been paid to the dependence of the observed daily variation on the solar-ecliptic latitude of the asymptotic direction.Seventy-three percent of the weeks considered in 1965 and 1966 give the phase of the first harmonic in a direction 85° ± 35 °E. Sixty percent of the weekly periods show a daily variation as a function of solar-ecliptic latitude which is in agreement with the Parker–Axford "streaming-velocity" theory. During Forbush decreases the diurnal phase shifts towards earlier hours and the amplitude increases to two to three times the predecrease level.

scholarly journals Ultrahigh Energy Cosmic-ray Accelerators

2000 ◽  
Vol 195 ◽  
pp. 303-310
Author(s):  
A. V. Olinto
Keyword(s):  
Angular Distribution ◽  
Neutron Star ◽  
Cosmic Rays ◽  
Cosmic Ray ◽  
High Energy ◽  
Ultrahigh Energy ◽  
Recent Proposal ◽  
Alternative Models ◽  
Isotropic Distribution ◽  
Energy Cutoff

The surprising lack of a high energy cutoff in the cosmic ray spectrum at the highest energies, together with an apparently isotropic distribution of arrival directions, have strongly challenged most models proposed for the acceleration of ultrahigh energy cosmic rays. Young neutron star winds may be able to explain the mystery. We discuss this recent proposal after summarizing the observational challenge and plausible acceleration sites. Young neutrons star winds differ from alternative models in the predictions for composition, spectrum, and angular distribution, which will be tested in future experiments.

The long-term variation of the cosmic radiation

1968 ◽  
Vol 46 (10) ◽  
pp. S903-S906 ◽  
Author(s):  
J. A. Lockwood ◽  
W. R. Webber
Keyword(s):  
Neutron Monitor ◽  
Cosmic Radiation ◽  
Cosmic Ray ◽  
Solar Modulation ◽  
Neutron Monitors ◽  
Cosmic Ray Intensity ◽  
Direct Measurements ◽  
Term Variation ◽  
Primary Cosmic Radiation

The variation in the cosmic-ray intensity recorded by neutron monitors from 1958 to 1965 has been investigated to deduce the form of the solar modulation of the cosmic radiation. The observed changes in the intensity at the neutron monitor stations, averaged over quarter-year periods, were compared with changes calculated using modulation functions depending upon energy, rigidity, and velocity × rigidity. These calculations were based upon the revised differential response functions deduced by Lockwood and Webber (1967). The variance between the observed and calculated changes in the neutron monitor intensities at different stations was minimized to determine the best form of the solar modulation function. We find that the change of the primary cosmic radiation, deduced from the change in the neutron monitor intensity as well as from direct measurements of the primary flux, can be described by a modulation of the form exp(–K/P) in the rigidity range 0.5 < P < 50 GV. The change between 1959 and 1965 can be fitted with K = 1.94 ± 0.09 and between 1963 and 1965 with K = 0.36 ± 0.05.

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