The Cosmic Ray Ground-level Enhancement of 24 October 1989

1994 ◽  
Vol 11 (1) ◽  
pp. 28-32 ◽  
Author(s):  
J. L. Cramp ◽  
J. E. Humble ◽  
M. L. Duldig
Keyword(s):  
Pitch Angle ◽  
Cosmic Ray ◽  
Ground Level ◽  
Model Fit ◽  
South Pole ◽  
Neutron Monitors ◽  
Ground Level Enhancement ◽  
Apparent Source ◽  
Worldwide Network ◽  
Monitor Data

AbstractThe cosmic ray ground-level enhancement (GLE) of 24 October 1989 was the last of a series of GLEs associated with the same solar active region. Intensity enhancements were observed by at least 31 neutron monitors in the worldwide network, with the largest increase (~200%) observed at South Pole, Antarctica around 20:30 UT. Using a least-squares model fit to all available neutron monitor data, spectra, apparent source directions and particle pitch angle distributions have been derived. The effect of disturbed geomagnetic conditions has also been taken into account.

INTERPLANETARY AND SOLAR PLASMA PARAMETERS OF THE 14 JULY 2000 GROUND LEVEL ENHANCEMENT

2003 ◽  
Vol 12 (02) ◽  
pp. 337-344 ◽  
Author(s):  
S. S. AL-THOYAIB
Keyword(s):  
Rapid Change ◽  
Cosmic Ray ◽  
Ground Level ◽  
Low Energy ◽  
Neutron Monitors ◽  
Ground Level Enhancement ◽  
Plasma Parameters ◽  
Cosmic Ray Intensity ◽  
The Difference ◽  
Galactic Cosmic Ray

The ground level enhancement (GLE) of 14 July 2000 observed in the cosmic ray intensity has been examined. The event was recorded only by neutron monitors. It has a complex intensity-time structure. The northern hemisphere stations (Thule, Goose Bay, and Oulu) recorded abrupt increases earlier by 10 minutes than those in the southern hemisphere. Due to the difference in sensitivity at rigidity less than ~3 GV, the considered detectors recorded different increases in count rates relative to galactic cosmic ray background. This paper presents the study of GLE associated with the X5.7 solar flare. The rapid change of arriving particles were anisotropic during the onset of the event; it become isotropic during the declining phase of the event, where only low energy protons remained. In addition, the observations of energetic solar particles and interplanetary parameters have been examined.

scholarly journals Spectra of variations and cosmic ray anisotropy during GLE of June 11, 1991

10.12737/7490 ◽  
2015 ◽  
Vol 1 (1) ◽  
pp. 115-120
Author(s):  
Марина Кравцова ◽  
Marina Kravtsova ◽  
Валерий Сдобнов ◽  
Valeriy Sdobnov
Keyword(s):  
Coordinate System ◽  
Exponential Function ◽  
Cosmic Ray ◽  
Ground Level ◽  
Satellite Observations ◽  
Ground Level Enhancement ◽  
Global Survey ◽  
The Earth ◽  
Worldwide Network

We have studied variation spectra and cosmic-ray (CR) anisotropy, using the ground-based and satellite observations of the CR intensity on the worldwide network of stations during the ground level enhancement (GLE) of June 11, 1991. The spectro-graphic global survey has been used. Variation spectra of primary CRs at different moments of the event are presented. Note that the CR variation spectra during this period are not described by a power or an exponential function of particle rigidity. The maximum rigidity, up to which the protons were accelerated on June 11, 1991, was ~2.8 GV (06:00 UT; i.e., two hours after GLE started). We show relative variations in the CR intensity in the geocentric solar ecliptic coordinate system during certain periods of the event under study. On June 11, 1991, the bidirectional anisotropy dominated in the distribution of particles with rigidity of 4 GV and 10 GV, which implies that the Earth passed the loop-like IMF structure.

scholarly journals Development of a ground level enhancement alarm system based upon neutron monitors

Space Weather ◽  
2006 ◽  
Vol 4 (10) ◽  
pp. n/a-n/a ◽  
Author(s):  
T. Kuwabara ◽  
J. W. Bieber ◽  
J. Clem ◽  
P. Evenson ◽  
R. Pyle
Keyword(s):  
Ground Level ◽  
Alarm System ◽  
Neutron Monitors ◽  
Ground Level Enhancement

scholarly journals Short- and Medium-Term Induced Ionization in the Earth Atmosphere by Galactic and Solar Cosmic Rays

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Alexander Mishev
Keyword(s):  
Cosmic Rays ◽  
Cosmic Ray ◽  
Ground Level ◽  
Galactic Cosmic Rays ◽  
Earth Atmosphere ◽  
Medium Term ◽  
Ground Level Enhancement ◽  
Solar Cosmic Rays ◽  
The Earth ◽  
Ionization Effect

The galactic cosmic rays are the main source of ionization in the troposphere of the Earth. Solar energetic particles of MeV energies cause an excess of ionization in the atmosphere, specifically over polar caps. The ionization effect during the major ground level enhancement 69 on January 20, 2005 is studied at various time scales. The estimation of ion rate is based on a recent numerical model for cosmic-ray-induced ionization. The ionization effect in the Earth atmosphere is obtained on the basis of solar proton energy spectra, reconstructed from GOES 11 measurements and subsequent full Monte Carlo simulation of cosmic-ray-induced atmospheric cascade. The evolution of atmospheric cascade is performed with CORSIKA 6.990 code using FLUKA 2011 and QGSJET II hadron interaction models. The atmospheric ion rate is explicitly obtained for various latitudes, namely, 40°N, 60°N and 80°N. The time evolution of obtained ion rates is presented. The short- and medium-term ionization effect is compared with the average effect due to galactic cosmic rays. It is demonstrated that ionization effect is significant only in subpolar and polar atmosphere during the major ground level enhancement of January 20, 2005. It is negative in troposphere at midlatitude, because of the accompanying Forbush effect.

scholarly journals Cosmic Ray Evidence for the Magnetic Configuration of the Heliosphere

1981 ◽  
Vol 94 ◽  
pp. 397-398
Author(s):  
H. S. Ahluwalia
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Cosmic Rays ◽  
Cosmic Ray ◽  
Ground Level ◽  
The Sun ◽  
Ground Level Enhancement ◽  
Solar Cosmic Rays ◽  
Pile Up ◽  
Scattered Component

Sekido and Murakami (1958) proposed the existence of the heliosphere to explain the scattered component of the solar cosmic rays. The heliosphere of their conception is a spherical shell around the sun. The shell contains a highly-irregular magnetic field and serves to scatter the cosmic rays emitted by the sun. It thereby gives rise to an isotropic component of solar cosmic rays, following the maximum in the ground level enhancement (GLE). Meyer et al. (1956) showed that a similar picture applies to the GLE of 23 February 1956. They conclude that the inner and outer radii of the shell should be 1.4 AU and 5 AU respectively. They suggest that a shell is formed by the “pile-up” of the solar wind under pressure exerted by the interstellar magnetic field, as suggested by Davis (1955).

Global Solar Magnetic Field and Cosmic Ray Ground Level Enhancement

Solar Physics ◽  
2019 ◽  
Vol 294 (9) ◽  
Author(s):  
G. N. Kichigin ◽  
M. V. Kravtsova ◽  
V. E. Sdobnov
Keyword(s):  
Magnetic Field ◽  
Solar Magnetic Field ◽  
Cosmic Ray ◽  
Ground Level ◽  
Ground Level Enhancement

SMALL COSMIC-RAY INCREASES MEASURED AT GROUND LEVEL, SEPTEMBER 3, 1960, JULY 18 AND JULY 20, 1961

1962 ◽  
Vol 40 (5) ◽  
pp. 540-549 ◽  
Author(s):  
B. G. Wilson ◽  
D. C. Rose ◽  
Margaret D. Wilson
Keyword(s):  
Cosmic Ray ◽  
Ground Level ◽  
Strong Impact ◽  
Impact Zone ◽  
Limited Data ◽  
Neutron Monitors ◽  
Small Magnitude ◽  
Cosmic Ray Intensity ◽  
Interplanetary Magnetic Fields ◽  
The Impact

Three small increases in cosmic-ray intensity, observed in high counting rate neutron monitors in Canada, are described and the results examined in relation to the impact zone effect with particular reference to recent studies by McCracken. Pronounced impact zone effects were observed during the July 18, 1961, event, the largest of these three increases, while the September 3, 1960, event showed no such effects. Considerations of the state of the interplanetary magnetic fields at these times show that these results are consistent with McCracken's explanations. The sharp rise to maximum of the July 20, 1961, increase would suggest strong impact zone effects, but such conclusions that can be drawn from the limited data and the small magnitude of the increase suggest that it does not conform with the usual pattern.

On the nature of some anomalies in the cosmic-ray distribution

1968 ◽  
Vol 46 (10) ◽  
pp. S614-S616 ◽  
Author(s):  
N. P. Chirkov ◽  
G. F. Krymsky ◽  
A. I. Kuzmin
Keyword(s):  
Magnetic Field ◽  
Diurnal Variation ◽  
Interplanetary Magnetic Field ◽  
Equatorial Plane ◽  
Geomagnetic Field ◽  
Cosmic Ray ◽  
Neutron Monitors ◽  
Vector Method ◽  
Worldwide Network ◽  
Northern And Southern Hemispheres

Diurnal and semidiurnal variations of the data from the worldwide network of neutron monitors during 1958 are analyzed using the receiving-vector method. It is shown that there exists an "antisymmetric" diurnal variation, i.e., a variation with opposite phases in the northern and southern hemispheres. After correction for the distortion due to the geomagnetic field, it is found that this variation has an amplitude of 0.03% and an hour of maximum at 21.5 hours in the northern hemisphere. If the variation is due to cosmic-ray screening in the interplanetary magnetic field, this field must have a slope of 7° with respect to the solar equatorial plane.

scholarly journals GLE events in 24th solar cycle

2018 ◽  
Vol 62 ◽  
pp. 01006
Author(s):  
Yury Balabin ◽  
Boris Gvozdevsky ◽  
Aleksei Germanenko ◽  
Eugeny Maurchev
Keyword(s):  
Solar Cycle ◽  
Cosmic Rays ◽  
Ground Level ◽  
Energy Spectra ◽  
Special Technique ◽  
Neutron Monitors ◽  
Ground Level Enhancement ◽  
Solar Cosmic Rays ◽  
The World ◽  
Current Cycle

Started in 2009, the 24th solar cycle is going to end. In 2015, the solar activity was at its maximum, turning down. According to many indices, this cycle turned out to be abnormal. For instance, in the previous, the 23rd cycle, the index such as the number of solar spots was as high as 175, compared with that of the 24th cycle, not exceeding 100. According to the number of GLE-events (ground level enhancement of solar cosmic rays, observed on neutron monitors), the current cycle also differs greatly from the previous ones. In the 23rd cycle, the number of great GLE-events was as high as four, and that of small and moderate being five. In the 24th cycle, only two GLE-events were recorded: GLE 71 (17.05.2012) и GLE 72 (10.09.2017), with the last event being of small amplitude (5%). The presence of the neutron monitors network data enables calculation of the energy spectrum and other parameters of solar cosmic rays. The GLEevents are processed by special technique developed at PGI. It is aimed at solving the inverse problem: based on the data from the world neutron monitors network, to obtain the parameters of solar cosmic rays energy spectra. Like the previous ones, GLE-events 71 and 72 were processed by this technique. The energetic spectra obtained were compared with those in other events of the previous cycles

Sign in / Sign up

Export Citation Format

Share Document