scholarly journals Galactic cosmic ray decreases associated with non-interacting magnetic clouds in the 23rd solar cycle

2013 ◽  
Vol 8 (S300) ◽  
pp. 483-484
Author(s):  
J. J. Masías-Meza ◽  
S. Dasso
Keyword(s):  
Solar Cycle ◽  
Cosmic Ray ◽  
Total Sample ◽  
Magnetic Clouds ◽  
Neutron Monitors ◽  
Interplanetary Coronal Mass Ejections ◽  
23Rd Solar Cycle ◽  
Preliminary Study ◽  
Galactic Cosmic Ray ◽  
Selection Of

AbstractSudden Galactic Cosmic Ray (GCR) intensity decreases are related to the passage of Interplanetary Coronal Mass Ejections (ICMEs). These phenomena are also known as Forbush Decreases (FDs). The deepest FDs are associated with the passage of Magnetic Clouds (MCs). In this preliminary study we select “non-interacting” MCs associated with FDs observed from ground Neutron Monitors in the period 1996-2009, with the aim of reducing the complexity and the number of parameters involved in the GCR-MC interactions. We introduce a method to determine properties of the “ejecta component” of the FD. We analyze properties of the ejecta component in combination with properties of MCs. From the resulting selection of events, we find that those FDs containing ejecta components show stronger correlations with MC parameters than our total sample of events.

scholarly journals Signs of geoeffective space weather events in cosmic rays during the first half of the solar cycle 24

2021 ◽  
pp. 119-124
Author(s):  
Agnieszka Gil ◽  
Renata Modzelewska ◽  
Szczepan Moskwa ◽  
Agnieszka Siluszyk ◽  
Marek Siluszyk ◽  
...  
Keyword(s):  
Solar Cycle ◽  
Space Weather ◽  
Transmission Lines ◽  
Cosmic Ray ◽  
Neutron Monitors ◽  
Time Intervals ◽  
Forbush Decreases ◽  
Solar Cycle 24 ◽  
Cycle 24 ◽  
Galactic Cosmic Ray

Solar originating events are continually evident in galactic cosmic ray (GCR) flux registered at the ground by neutron monitors. We analyze time intervals of sporadic Forbush decreases (Fd) observed by neutron monitors (NM) during the first half of solar cycle 24. We consider NMs data, as well as, solar, heliospheric and geoma - gnetic activity parameters, around those periods, using different mathematical tools. Subsequently, an impact of space weather phenomena on energy infrastructure is well known, in the further step we consider logs from one of the Polish transmission lines operators during the time intervals of Fds. Based on the data from the Ins- titute of Meteorology and Water Management-Polish National Research Institute we exclude from the analysis the weather-related failures. We found that the increase in the superposed averaged number of failures appears around Forbush decreases.

scholarly journals Galactic Cosmic Ray Modulation Up to Recent Solar Cycles

2011 ◽  
Vol 48 (4) ◽  
pp. 66-70
Author(s):  
R. Agarwal ◽  
R. Mishra
Keyword(s):  
Solar Cycle ◽  
Solar Radio ◽  
Cosmic Ray ◽  
Radio Flux ◽  
Solar Cycles ◽  
Cosmic Ray Intensity ◽  
Cosmic Ray Modulation ◽  
Solar Radio Flux ◽  
Yearly Average ◽  
Galactic Cosmic Ray

Galactic Cosmic Ray Modulation Up to Recent Solar Cycles Cosmic ray neutron monitor counts obtained by different ground-based detectors have been used to study the galactic cosmic ray modulation during the last four solar activity cycles. Since long, systematic correlative studies have been per-formed to establish a significant relationship between the cosmic ray intensity and different helio-spheric activity parameters, and the study is extended to a recent solar cycle (23). In the present work, the yearly average of 10.7 cm solar radio flux and the interplanetary magnetic field strength (IMF, B) have been used to find correlation of the yearly average cosmic ray intensity derived from different neutron monitors. It is found that for four solar cycles (20-23) the cosmic ray intensity is anti-correlated with the 10.7 cm solar radio flux and the IMF, B value with some discrepancy. However, this is in a good positive correlation with the flux of mentioned wavelength for four different solar cycles. The IMF, B shows a weak correlation with cosmic rays for solar cycle 20, and a good anti-correlation for solar cycles 21-23.

scholarly journals On the Solar Cycle Variation of the Solar Diurnal Anisotropy of Multi-TeV Cosmic-ray Intensity Observed with the Tibet Air Shower Array

2019 ◽  
Vol 208 ◽  
pp. 08012
Author(s):  
M. Amenomori ◽  
X. J. Bi ◽  
D. Chen ◽  
T. L. Chen ◽  
W. Y. Chen ◽  
...  
Keyword(s):  
Solar Cycle ◽  
Cosmic Ray ◽  
Local Solar Time ◽  
Solar Cycle Variation ◽  
Cosmic Ray Intensity ◽  
Air Shower ◽  
23Rd Solar Cycle ◽  
Diurnal Anisotropy ◽  
Shower Array ◽  
Air Shower Array

We analyze the temporal variation of the solar diurnal anisotropy of the multi-TeV cosmic-ray intensity observed with the Tibet air shower array from 2000 to 2009, covering the maximum and minimum of the 23rd solar cycle. We comfirm that a remarkable additional anisotropy component is superposed on the Compton-Getting anisotropy at 4.0 TeV, while its amplitude decreases at higher energy regions. In constrast to the additional anisotropy reported by the Matsushiro experiment at 0.6 TeV, we find the residual component measured by Tibet at multi-TeV energies is consistent with being stable, with a fairly constant amplitude of 0.041% ± 0.003% and a phase at around 07.17 ± 00.16 local solar time at 4.0 TeV. This suggests the additional anisotropy observed by the Tibet experiment could result from mechanisms unrelated to solar activities.

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