Study of the development and mechanism of large amplitude decreases in cosmic ray intensity during geomagnetic disturbances in the magnetosphere

Author(s):  
B. Badruddin ◽  
O.P.M. Aslam ◽  
M. Derouich ◽  
S. Qutub
2005 ◽  
Vol 20 (29) ◽  
pp. 6717-6719 ◽  
Author(s):  
S. K. MISHRA ◽  
D. P. TIWARI ◽  
S. C. KAUSHIK

Transient decrease in cosmic ray intensity following by a slow recovery typically lasting for several days is identified as Forbush decrease (Fd) event. As a result the geomagnetic index (Dst) decreased up to 300 nT, indicating a large geomagnetic storm and the percentage Fd decrease has gone to 16% giving rise a cosmic ray storm. Both events coincided with interplanetary conditions. Therefore, a systematic study has been performed to investigate the variation of cosmic ray intensity along with the interplanetary and geomagnetic disturbances. Results indicate a strong relationship between geomagnetic activity and Forbush decrease on short-term basis. Two types of interplanetary transient disturbances, namely magnetic cloud events and bidirectional events are analyzed to study the short-term changes in the solar wind (SW) plasma components as well as in cosmic ray intensity.


2008 ◽  
Vol 4 (S257) ◽  
pp. 451-456
Author(s):  
E. Eroshenko ◽  
A. Belov ◽  
H. Mavromichalaki ◽  
V. Oleneva ◽  
A. Papaioannou ◽  
...  

AbstractThe Forbush effects associated with far western and eastern powerful sources on the Sun that occurred on the background of unsettled and moderate interplanetary and geomagnetic disturbances have been studied by data from neutron monitor networks and relevant measurements of the solar wind parameters. These Forbush effects may be referred to a special sub-class of events, with the characteristics like the event in July 2005, and incorporated by the common conditions: absence of a significant disturbance in the Earth vicinity; absence of a strong geomagnetic storm; slow decrease of cosmic ray intensity during the main phase of the Forbush effect. General features and separate properties in behavior of density and anisotropy of 10 GV cosmic rays for this subclass are investigated.


2011 ◽  
Vol 7 (3) ◽  
pp. 373-377 ◽  
Author(s):  
M. Papailiou ◽  
H. Mavromichalaki ◽  
K. Kudela ◽  
J. Stetiarova ◽  
S. Dimitrova ◽  
...  

Solar Physics ◽  
2017 ◽  
Vol 292 (10) ◽  
Author(s):  
Binod Adhikari ◽  
Nirakar Sapkota ◽  
Prashrit Baruwal ◽  
Narayan P. Chapagain ◽  
Carlos Roberto Braga

1959 ◽  
Vol 37 (9) ◽  
pp. 970-982 ◽  
Author(s):  
A. G. Fenton ◽  
K. G. McCracken ◽  
D. C. Rose ◽  
B. G. Wilson

The onset times of a number of Forbush-type decreases observed at four widely spaced stations are compared, and it is shown that appreciable differences occur. The stations selected were Hobart, Mawson, Ottawa, and Sulphur Mountain. It was found that a consistent pattern is obtained for the events studied when the onset times are plotted as a function of the direction of maximum sensitivity of the recorders relative to the earth-sun line. This is interpreted as being due to a directional anisotropy that exists in the mechanism producing the decreases, at least in the early stages. The depression occurs first for particles arriving from directions between 30° and 120° west of the earth–sun line. The relation between these observations and geomagnetic disturbances and the quiet-day daily variation is discussed.


Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1613
Author(s):  
Helen Mavromichalaki ◽  
Maria-Christina Papailiou ◽  
Maria Gerontidou ◽  
Svetla Dimitrova ◽  
Karel Kudela

It is well known that the various manifestations of space weather can influence a wide range of human activities, from technological systems to human health. Various earlier, as well as more recent multi-disciplinary heliobiological and biometeorological studies have revealed that the human organism is sensitive to environmental physical activity changes and reacts to them through variations of the physiological parameters of the human body. This paper constitutes an overview of the National and Kapodistrian University of Athens investigations in regard to the possible effect of solar, geomagnetic, and cosmic ray activity on human physiological parameters. The Athens Cosmic Ray and Solar Physics Groups collaborated with scientific teams from different countries, statistically processing and analyzing data related to human physiological parameters (such as mean heart rate, arterial systolic, and diastolic pressure), or the number of incidents of different types of cardiac arrhythmias and so forth, in relation to data concerning and describing geomagnetic activity (geomagnetic indices Ap and Dst) and variations in cosmic ray intensity (Forbush decreases and cosmic ray intensity enhancements). In total, four projects were carried out concerning data from different geographical regions (Baku, Azerbaijan; Kosice, Slovakia; Tbilisi, Georgia; Piraeus, Greece), covering different time periods and time scales (daily data or yearly data), and referring to different groups of individuals (selected healthy persons or random persons). The studies concluded with interesting results concerning the possible influence of geomagnetic and cosmic ray activity on the human physiological state.


2005 ◽  
Vol 20 (29) ◽  
pp. 6699-6701 ◽  
Author(s):  
S. P. KAVLAKOV

It was shown that specific changes of the sunspots (SS) number, cosmic ray (CR) intensity and geomagnetic activity indices AP and KP were statistically noticeable in the interval of 30 days before the appearance of a cyclonic rotational system over the North Atlantic, developing gradually in a major hurricane.


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