Force-field parameterization of the galactic cosmic ray spectrum: Validation for Forbush decreases

2015 ◽  
Vol 55 (12) ◽  
pp. 2940-2945 ◽  
Author(s):  
I.G. Usoskin ◽  
G.A. Kovaltsov ◽  
O. Adriani ◽  
G.C. Barbarino ◽  
G.A. Bazilevskaya ◽  
...  
Keyword(s):  
Force Field ◽  
Cosmic Ray ◽  
Forbush Decreases ◽  
Force Field Parameterization ◽  
Galactic Cosmic Ray

A comparison of catalogues of Forbush decreases identified from individual and a network of neutron monitors: a critical perspective

2021 ◽  
Vol 503 (4) ◽  
pp. 5675-5691
Author(s):  
O Okike ◽  
J A Alhassan ◽  
E U Iyida ◽  
A E Chukwude
Keyword(s):  
Cosmic Ray ◽  
Radiowave Propagation ◽  
Current Work ◽  
Survey Method ◽  
Critical Perspective ◽  
Short Term ◽  
Forbush Decreases ◽  
Academy Of Sciences ◽  
Galactic Cosmic Ray ◽  
Monitor Data

ABSTRACT Short-term rapid depressions in Galactic cosmic ray (GCR) flux, historically referred to as Forbush decreases (FDs), have long been recognized as important events in the observation of cosmic ray (CR) activity. Although theories and empirical results on the causes, characteristics, and varieties of FDs have been well established, detection of FDs, from either isolated detectors' or arrays of neutron monitor data, remains a subject of interest. Efforts to create large catalogues of FDs began in the 1990s and have continued to the present. In an attempt to test some of the proposed CR theories, several analyses have been conducted based on the available lists. Nevertheless, the results obtained depend on the FD catalogues used. This suggests a need for an examination of consistency between FD catalogues. This is the aim of the present study. Some existing lists of FDs, as well as FD catalogues developed in the current work, were compared, with an emphasis on the FD catalogues selected by the global survey method (GSM). The Forbush effects and interplanetary disturbances database (FEID), created by the Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radiowave Propagation Russian Academy of Sciences (IZMIRAN), is the only available comprehensive and up to date FD catalogue. While there are significant disparities between the IZMIRAN FD and other event lists, there is a beautiful agreement between FDs identified in the current work and those in the FEID. This may be a pointer to the efficiency of the GSM and the automated approach to FD event detection presented here.

Solar Modulation of Galactic Cosmic-Ray Protons Based on a Modified Force-field Approach

2021 ◽  
Vol 921 (2) ◽  
pp. 109
Author(s):  
Zhenning Shen ◽  
Hao Yang ◽  
Pingbing Zuo ◽  
Gang Qin ◽  
Fengsi Wei ◽  
...  
Keyword(s):  
Force Field ◽  
Cosmic Ray ◽  
Solar Modulation ◽  
Field Approach ◽  
Galactic Cosmic Ray

Testing the Impact of Coronal Mass Ejections on Cosmic Ray Intensity Modulation with Algorithm selected Forbush Decreases

2020 ◽  
Author(s):  
O Okike ◽  
O C Nwuzor ◽  
F C Odo ◽  
E U Iyida ◽  
J E Ekpe ◽  
...  
Keyword(s):  
Coronal Mass Ejections ◽  
Cosmic Ray ◽  
Forbush Decreases ◽  
Cosmic Ray Intensity ◽  
Event Identification ◽  
Diurnal Anisotropy ◽  
Current Article ◽  
Galactic Cosmic Ray ◽  
The Impact ◽  
The Relationship

Abstract The relationship between coronal mass ejections (CMEs) and Forbush decreases (FDs) has been investigated in the past. But selection of both solar events are difficult. Researchers have developed manual and automated methods in efforts to identify CMEs as well as FDs. While scientists investigating CMEs have made significant advancement, leading to several CME catalogues, including manual and automated events catalogues, those analyzing FDs have recorded relatively less progress. Till date, there are no comprehensive manual FD catalogues, for example. There are also paucity of Automated FD lists. Many investigators, therefore, attempt to manually select FDs which are subsequently used in the analysis of the impact of CMEs on galactic cosmic ray (GCR) flux depressions. However, some of the CME versus FD correlation results might be biased since manual event identification is usually subjective, unable to account for the presence of solar-diurnal anisotropy which characterizes GCR flux variations. The current article investigates the relation between CMEs and FDs with emphasis on accurate and careful Forbush event selection.

scholarly journals Possible effects on Earth's climate due to reduced atmospheric ionization by GCR during Forbush Decreases

2016 ◽  
Vol 12 (S328) ◽  
pp. 298-300
Author(s):  
Williamary Portugal ◽  
Ezequiel Echer ◽  
Mariza Pereira de Souza Echer ◽  
Alessandra Abe Pacini
Keyword(s):  
Surface Temperature ◽  
Chemical Properties ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Forbush Decreases ◽  
First Results ◽  
Earth’S Climate ◽  
Galactic Cosmic Ray ◽  
Cosmic Ray Flux ◽  
Atmospheric Ionization

AbstractThis work presents the first results of a study about possible effects on the surface temperature during short periods of lower fluxes of Galactic Cosmic Rays at Earth, called Forbush Decreases. There is a hypothesis that the Galactic Cosmic Ray flux decreases cause changes on the physical-chemical properties of the atmosphere. We have conducted a study to investigate these possible effects on several latitudinal regions, around the ten strongest FDs occurred from 1987 to 2015. We have found a possible increase on the surface temperature at middle and high latitudes during the occurence of these events.

Utilizing galactic cosmic rays as signatures of coronal mass ejections

2021 ◽  
Author(s):  
Mateja Dumbovic
Keyword(s):  
Coronal Mass Ejections ◽  
Interplanetary Space ◽  
Flux Rope ◽  
Forbush Decrease ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Forbush Decreases ◽  
Magnetic Structures ◽  
Different Types ◽  
Galactic Cosmic Ray

<p>Coronal mass ejections (CMEs) are the most violent eruptions in the solar system. They are one of the main drivers of the heliospheric variability and cause various interplanetary as well as planetary disturbances. One of their very common in-situ signatures are short-term reductions in the galactic cosmic ray (GCR) flux (i.e. Forbush decreases), which are measured by ground-based instruments at Earth and Mars, as well as various spacecraft throughout the heliosphere (most recently by Solar Orbiter). In general, interplanetary magnetic structures interact with GCRs producing depressions in the GCR flux. Therefore, different types of interplanetary magnetic structures cause different types of GCR depressions, allowing us to distinguish between them. In the interplanetary space the CME typically consists of two structures: the presumably closed flux rope and the shock/sheath which is formed ahead of the flux rope as it propagates and expands in the interplanetary space. Interaction of GCRs with these two structures is modelled separately, where the flux-rope related Forbush decrease can be modelled assuming that the GCRs diffuse slowly into the expanding flux rope, which is initially empty at its center (ForbMod model). The resulting Forbush decrease at a given time, i.e. heliospheric distance, reflects the evolutionary properties of CMEs. However, ForbMod is not yet able to take into account complex, non-self-similar evolution of the flux rope. Nevertheless, Forbush decreases can undoubtedly give us information on the CMEs in the heliosphere, especially where other measurements are lacking, and with further development, Forbush decrease reverse modelling could provide insight into the CME evolution.</p>

scholarly journals Investigation of the relation between space-weather parameters and Forbush decreases automatically selected from Moscow and Apatity cosmic ray stations during solar cycle 23

2021 ◽  
Vol 21 (11) ◽  
pp. 273
Author(s):  
Jibrin Adejoh Alhassan ◽  
Ogbonnaya Okike ◽  
Augustine Ejikeme Chukwude
Keyword(s):  
Solar Cycle ◽  
Space Weather ◽  
Cosmic Ray ◽  
Computer Code ◽  
Weather Data ◽  
Forbush Decreases ◽  
Two Samples ◽  
Solar Cycle 23 ◽  
Weather Parameters ◽  
Galactic Cosmic Ray

Abstract We present the results of an investigation of the relation between space-weather parameters and cosmic ray (CR) intensity modulation using algorithm-selected Forbush decreases (FDs) from Moscow (MOSC) and Apatity (APTY) neutron monitor (NM) stations during solar cycle 23. Our FD location program detected 408 and 383 FDs from MOSC and APTY NM stations respectively. A coincident computer code employed in this work detected 229 FDs that were observed at the same Universal Time (UT) at the two stations. Out of the 229 simultaneous FDs, we formed a subset of 139 large FDs(%) ≤ − 4 at the MOSC station. We performed a two-dimensional regression analysis between the FD magnitudes and the space-weather data on the two samples. We find that there were significant space-weather disturbances at the time of the CR flux depressions. The correlation between the space-weather parameters and decreases in galactic cosmic ray (GCR) intensity at the two NM stations is statistically significant. The implications of the present space-weather data on CR intensity depressions are highlighted.

scholarly journals Galactic Cosmic-Ray Anisotropy During Forbush Decreases: Evidence for Diffusive Barriers and Large-Scale Flow

2019 ◽  
Author(s):  
Grace Ihongo ◽  
D. Ruffolo ◽  
A. Saiz ◽  
U. Tortermpun ◽  
A. C-L. Chian
Keyword(s):  
Large Scale ◽  
Cosmic Ray ◽  
Forbush Decreases ◽  
Large Scale Flow ◽  
Galactic Cosmic Ray
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