Solar-cycle dependence of the Sun's apparent radius in the neutral iron spectral line at 525 nm

Nature ◽  
1995 ◽  
Vol 377 (6546) ◽  
pp. 214-215 ◽  
Author(s):  
R. K. Ulrich ◽  
L. Bertello
Keyword(s):  
Solar Cycle ◽  
Spectral Line ◽  
Cycle Dependence

Solar cycle dependence of the solar wind dynamics: Pioneer Voyager, and Ulysses from 1 to 5 AU

1996 ◽  
Vol 101 (A11) ◽  
pp. 24359-24371 ◽  
Author(s):  
J. Américo González-Esparza ◽  
Edward J. Smith
Keyword(s):  
Solar Wind ◽  
Solar Cycle ◽  
Cycle Dependence

Solar cycle dependence and long-term trends in the wind field of the mesosphere/lower thermosphere

1997 ◽  
Vol 59 (5) ◽  
pp. 497-509 ◽  
Author(s):  
J. Bremer ◽  
R. Schminder ◽  
K.M. Greisiger ◽  
P. Hoffmann ◽  
D. Kürschner ◽  
...  
Keyword(s):  
Solar Cycle ◽  
Wind Field ◽  
Lower Thermosphere ◽  
Long Term Trends ◽  
Cycle Dependence

scholarly journals Predicting Solar Flares with Machine Learning: Investigating Solar Cycle Dependence

2020 ◽  
Vol 895 (1) ◽  
pp. 3
Author(s):  
Xiantong Wang ◽  
Yang Chen ◽  
Gabor Toth ◽  
Ward B. Manchester ◽  
Tamas I. Gombosi ◽  
...  
Keyword(s):  
Machine Learning ◽  
Solar Cycle ◽  
Solar Flares ◽  
Cycle Dependence

A Search for Periodic Variations in Geomagnetic Activity and Their Solar Cycle Dependence

1973 ◽  
Vol 7 (3) ◽  
pp. 135-140 ◽  
Author(s):  
H Hauska ◽  
S Abdel-Wahab ◽  
E Dyring
Keyword(s):  
Solar Cycle ◽  
Geomagnetic Activity ◽  
Cycle Dependence

scholarly journals Solar cycle dependence of scaling in solar wind fluctuations

2008 ◽  
Vol 15 (3) ◽  
pp. 445-455 ◽  
Author(s):  
S. C. Chapman ◽  
B. Hnat ◽  
K. Kiyani
Keyword(s):  
Solar Wind ◽  
Solar Cycle ◽  
Momentum Flux ◽  
Magnetic Fluctuations ◽  
Mhd Turbulence ◽  
Scaling Properties ◽  
Two Component ◽  
Energy And Momentum ◽  
Cycle Dependence

Abstract. In this review we collate recent results for the statistical scaling properties of fluctuations in the solar wind with a view to synthesizing two descriptions: that of evolving MHD turbulence and that of a scaling signature of coronal origin that passively propagates with the solar wind. The scenario that emerges is that of coexistent signatures which map onto the well known "two component" picture of solar wind magnetic fluctuations. This highlights the need to consider quantities which track Alfvénic fluctuations, and energy and momentum flux densities to obtain a complete description of solar wind fluctuations.

scholarly journals Long-term evolution of sunspot magnetic fields

2010 ◽  
Vol 6 (S273) ◽  
pp. 126-133 ◽  
Author(s):  
Matthew J. Penn ◽  
William Livingston
Keyword(s):  
Solar Cycle ◽  
Magnetic Fields ◽  
Spectral Line ◽  
Detailed Examination ◽  
Temporal Variations ◽  
Line Of Sight ◽  
Data Sets ◽  
Infrared Spectral ◽  
Cycle 24 ◽  
Synoptic Observations

AbstractIndependent of the normal solar cycle, a decrease in the sunspot magnetic field strength has been observed using the Zeeman-split 1564.8nm Fe I spectral line at the NSO Kitt Peak McMath-Pierce telescope. Corresponding changes in sunspot brightness and the strength of molecular absorption lines were also seen. This trend was seen to continue in observations of the first sunspots of the new solar Cycle 24, and extrapolating a linear fit to this trend would lead to only half the number of spots in Cycle 24 compared to Cycle 23, and imply virtually no sunspots in Cycle 25.We examined synoptic observations from the NSO Kitt Peak Vacuum Telescope and initially (with 4000 spots) found a change in sunspot brightness which roughly agreed with the infrared observations. A more detailed examination (with 13,000 spots) of both spot brightness and line-of-sight magnetic flux reveals that the relationship of the sunspot magnetic fields with spot brightness and size remain constant during the solar cycle. There are only small temporal variations in the spot brightness, size, and line-of-sight flux seen in this larger sample. Because of the apparent disagreement between the two data sets, we discuss how the infrared spectral line provides a uniquely direct measurement of the magnetic fields in sunspots.

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