scholarly journals Middle and low latitudes hemispheric asymmetries in ∑O/N2 and TEC during intense magnetic storms of Solar Cycle 24

Author(s):  
Waqar Younas ◽  
Majid Khan ◽  
C. Amory-Mazaudier ◽  
Paul O. Amaechi ◽  
R. Fleury
2021 ◽  
Author(s):  
Adamantia Zoe Boutsi ◽  
Georgios Balasis ◽  
Ioannis A. Daglis ◽  
Kanaris Tsinganos ◽  
Omiros Giannakis

<p>Geomagnetically Induced Currents (GIC) constitute an integral part of the space weather research and a subject of ever-growing attention for countries located in the low and middle latitudes. A series of recent studies highlights the importance of considering GIC risks for the Mediterranean region. Here, we exploit data from the HellENIc GeoMagnetic Array (ENIGMA), which is located in Greece, complemented by magnetic observatories in Italy, to calculate corresponding values of the GIC index, i.e., a proxy of the geoelectric field calculated entirely from geomagnetic field variations. We perform our analysis for the most intense magnetic storms (Dst<-150 nT) of solar cycle 24. Our results show a good correlation between the storm sudden commencement (SSC) and an increase of the GIC index value. These investigations indicate that despite the elevated amplitude of the GIC index the associated risk remains at low level for the power networks in Greece and Italy during the considered storm events.</p>


2014 ◽  
Vol 4 (2) ◽  
pp. 477-483
Author(s):  
Debojyoti Halder

Sunspots are temporary phenomena on the photosphere of the Sun which appear visibly as dark spots compared to surrounding regions. Sunspot populations usually rise fast but fall more slowly when observed for any particular solar cycle. The sunspot numbers for the current cycle 24 and the previous three cycles have been plotted for duration of first four years for each of them. It appears that the value of peak sunspot number for solar cycle 24 is smaller than the three preceding cycles. When regression analysis is made it exhibits a trend of slow rising phase of the cycle 24 compared to previous three cycles. Our analysis further shows that cycle 24 is approaching to a longer-period but with smaller occurrences of sunspot number.


Solar Physics ◽  
2015 ◽  
Vol 290 (5) ◽  
pp. 1417-1427 ◽  
Author(s):  
A. Shanmugaraju ◽  
M. Syed Ibrahim ◽  
Y.-J. Moon ◽  
A. Mujiber Rahman ◽  
S. Umapathy

Space Weather ◽  
2017 ◽  
Vol 15 (12) ◽  
pp. 1649-1660 ◽  
Author(s):  
E. M. B. Thiemann ◽  
M. Dominique ◽  
M. D. Pilinski ◽  
F. G. Eparvier

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