Solar activity and the associated ground level enhancements of solar cosmic rays during solar cycle 23

2011 ◽  
Vol 7 (4) ◽  
pp. 439-443 ◽  
Author(s):  
M. Andriopoulou ◽  
H. Mavromichalaki ◽  
P. Preka-Papadema ◽  
C. Plainaki ◽  
A. Belov ◽  
...  
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Cosmic Rays ◽  
Ground Level ◽  
Solar Cosmic Rays ◽  
Solar Cycle 23 ◽  
Ground Level Enhancements

scholarly journals Retrospective analysis of GLEs and estimates of radiation risks

2018 ◽  
Vol 8 ◽  
pp. A52 ◽  
Author(s):  
Leonty I. Miroshnichenko
Keyword(s):  
Solar Activity ◽  
Ground Level ◽  
Radiation Hazard ◽  
Occurrence Rate ◽  
Solar Cosmic Rays ◽  
Dose Rates ◽  
Recent Debate ◽  
Unique Distribution ◽  
Different Levels ◽  
Ground Level Enhancements

28 February 2017 marked 75 years since the first confident registration of solar cosmic rays (SCRs), i.e., accelerated solar particles with energies from about 106 to ~1010 ÷ 1011 eV. Modern state of the problems related to the studies of Ground Level Enhancements (GLEs) of relativistic SCRs is critically analyzed based on available direct and proxy data. We are also taking into account extremely large fluxes of non-relativistic solar energetic particles (SEPs). Both kinds of SCR events are of great astrophysical and geo-scientific (geophysical) interests. A number of the GLE properties (total statistics, occurrence rate, longitude distribution, ranking of GLEs, a number of specific GLEs – so-called “rogue” SEP events etc.) are discussed in some detail. We note also the problems of GLE identification (definition) by ground-based observations, the difficulties in the studies of weak (“hidden”, or sub-) GLEs etc. One of serious challenges to the problem of radiation hazard in space is a lack of a clear, unambiguous relation between the fluxes (fluences) of relativistic SCR and non-relativistic SEPs. Special attention is paid to the recent debate on the validity, origin and properties of the “ancient” events AD775, AD994, AD1859 (Carrington event) and BC3372. We demonstrate that, in spite of existing uncertainties in proton fluences above 30 MeV, all of them are fitted well by a unique distribution function, at least, with the present level of solar activity. Extremely large SEP events are shown to obey a probabilistic distribution on their fluences with a sharp break in the range of large fluences (or low probabilities). The studies of this kind may be extended for periods with different levels of solar activity in the past and/or in the future. Dose rates at aircraft altitudes are also demonstrated during some GLEs. Several examples of using the SCR data and GLE properties in radiation prediction schemes are considered.

Ground level enhancements of solar cosmic rays during the last three solar cycles

2010 ◽  
Vol 50 (1) ◽  
pp. 21-33 ◽  
Author(s):  
A. V. Belov ◽  
E. A. Eroshenko ◽  
O. N. Kryakunova ◽  
V. G. Kurt ◽  
V. G. Yanke
Keyword(s):  
Cosmic Rays ◽  
Ground Level ◽  
Solar Cycles ◽  
Solar Cosmic Rays ◽  
Ground Level Enhancements

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

Possible ground level enhancements of solar cosmic rays in 2012

2015 ◽  
Vol 79 (5) ◽  
pp. 561-565 ◽  
Author(s):  
A. V. Belov ◽  
E. A. Eroshenko ◽  
O. N. Kryakunova ◽  
N. F. Nikolayevskiy ◽  
A. M. Malimbayev ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Ground Level ◽  
Solar Cosmic Rays ◽  
Ground Level Enhancements
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