LASCO FeXIV and FeX observations of the solar coronal rotation during the recent solar activity minimum

1999 ◽  
Author(s):  
B. Inhester ◽  
G. Stenborg ◽  
R. Schwenn ◽  
N. Srivastava ◽  
B. Podlipnik
Keyword(s):  
Solar Activity ◽  
Solar Activity Minimum ◽  
Coronal Rotation ◽  
Solar Coronal

scholarly journals Evidence of a strong relationship between hemispheric asymmetry in solar coronal rotation and solar activity during solar cycle 24

2020 ◽  
Vol 499 (4) ◽  
pp. 5442-5446
Author(s):  
Jaidev Sharma ◽  
Anil K Malik ◽  
Brajesh Kumar ◽  
Hari Om Vats
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Rotation Rate ◽  
Hemispheric Asymmetry ◽  
Solar Rotation ◽  
Strong Relationship ◽  
Space Mission ◽  
Asymmetry Index ◽  
Coronal Rotation ◽  
Solar Coronal

ABSTRACT In this paper, we report evidence of a very strong and statistically significant relationship between hemispheric asymmetry in the solar coronal rotation rate and solar activity. Our approach is based on the cross-correlation of the hemispheric asymmetry index (AI) in the rotation rate with annual solar activity indicators. To obtain the hemispheric asymmetry in the solar rotation rate, we use solar full disc (SFD) images at 30.4-, 19.5- and 28.4-nm wavelengths for the 24th solar cycle, that is, for the period from 2008 to 2018, as recorded by the Solar Terrestrial Relations Observatory (STEREO) space mission. Our analysis shows that the hemispheric asymmetry in rotation rate is high during the solar maxima from 2011 to 2014. However, hemispheric asymmetry decreases gradually on both sides (i.e. from 2008 to 2011 and from 2014 to 2018). The results show that the AI leads sunspot numbers by ∼ 1.56 yr. This is a clear indication that hemispheric asymmetry triggers the formation of sunspots in conjunction with the differential rotation of the Sun.

Nitrate abundance in polar ice during the great solar activity minimum

2002 ◽  
Vol 29 (11) ◽  
pp. 1707-1711 ◽  
Author(s):  
O.G. Gladysheva ◽  
G.E. Kocharov ◽  
G.A. Kovaltsov ◽  
I.G. Usoskin
Keyword(s):  
Solar Activity ◽  
Polar Ice ◽  
Solar Activity Minimum

scholarly journals The Observed Relationships Between Some Solar Rotation Parameters and the Activity Cycle

1983 ◽  
Vol 102 ◽  
pp. 99-111
Author(s):  
Robert Howard ◽  
Barry J. LaBonte
Keyword(s):  
Solar Activity ◽  
Solar Rotation ◽  
Rotational Velocity ◽  
Torsional Oscillation ◽  
Periodic Oscillation ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Solar Activity Minimum ◽  
Activity Maximum ◽  
Open Question

Several parameters of the solar rotation show variations which appear to relate to the phase of the solar activity cycle. The latitude gradient of the differential rotation, as seen in the coefficients of the sin2 and sin4 terms in the latitude expansion, shows marked variations with the cycle. One of these variations may be described as a one-cycle-per-hemisphere torsional oscillation with a period of 11 years, where the high latitudes rotate faster at solar activity maximum and slower at minimum, and the low latitudes rotate faster at solar activity minimum and slower at maximum. Another variation is a periodic oscillation of the fractional difference in the low-latitude rotation between north and south hemispheres. The possibility of a variation in the absolute rotational velocity of the sun in phase with the solar cycle remains an open question. The two-cycle-per-hemisphere torsional waves in the solar rotation also represent an aspect of the rotation which varies with the cycle. We show that the amplitude of the fast flowing zone rises a year before the rise to activity maximum. The fast zone seems to be physically the more significant of the two zones.

Interplanetary scintillations of an ensemble of radio sources during the solar activity minimum of cycles 23/24

2013 ◽  
Vol 51 (1) ◽  
pp. 23-28 ◽  
Author(s):  
I. V. Chashei ◽  
V. I. Shishov ◽  
S. A. Tyul’bashev ◽  
A. V. Glyantsev ◽  
I. A. Subaev
Keyword(s):  
Solar Activity ◽  
Radio Sources ◽  
Solar Activity Minimum ◽  
Interplanetary Scintillations
Sign in / Sign up

Export Citation Format

Share Document