scholarly journals ON THE CONSTANCY OF THE DIAMETER OF THE SUN DURING THE RISING PHASE OF SOLAR CYCLE 24

2015 ◽  
Vol 808 (1) ◽  
pp. 4 ◽  
Author(s):  
M. Meftah ◽  
A. Hauchecorne ◽  
A. Irbah ◽  
T. Corbard ◽  
R. Ikhlef ◽  
...  
Keyword(s):  
Solar Cycle ◽  
The Sun ◽  
Solar Cycle 24 ◽  
Cycle 24

Regression Analysis of Sunspot Numbers for the Solar Cycle 24 in Comparison to Previous Three Cycles

2014 ◽  
Vol 4 (2) ◽  
pp. 477-483
Author(s):  
Debojyoti Halder
Keyword(s):  
Regression Analysis ◽  
Solar Cycle ◽  
Sunspot Number ◽  
The Sun ◽  
Sunspot Numbers ◽  
Solar Cycle 24 ◽  
Current Cycle ◽  
Cycle 24

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.

X-Ray Flares and Activity Complexes on the Sun in Solar Cycle 24

2020 ◽  
Vol 64 (1) ◽  
pp. 58-65 ◽  
Author(s):  
E. S. Isaeva ◽  
V. M. Tomozov ◽  
S. A. Yazev
Keyword(s):  
Solar Cycle ◽  
The Sun ◽  
X Ray ◽  
Solar Cycle 24 ◽  
Cycle 24

Synoptic maps in three wavelengths of the Chromospheric Telescope

2018 ◽  
Vol 14 (A30) ◽  
pp. 339-341
Author(s):  
Andrea Diercke ◽  
Carsten Denker
Keyword(s):  
Time Series ◽  
Solar Cycle ◽  
Solar Disk ◽  
The Sun ◽  
Observational Period ◽  
Quiet Sun ◽  
Solar Cycle 24 ◽  
Cycle 24 ◽  
Spectral Ranges ◽  
Full Disk

Abstracthe Chromospheric Telescope (ChroTel) observes the entire solar disk since 2011 in three different chromospheric wavelengths: Hα, Ca ii K, and He i. The instrument records full-disk images of the Sun every three minutes in these different spectral ranges. The ChroTel observations cover the rising and decaying phase of solar cycle 24. We started analyzing the ChroTel time-series and created synoptic maps of the entire observational period in all three wavelength bands. The maps will be used to analyze the poleward migration of quiet-Sun filaments in solar cycle 24.

scholarly journals Predicting amplitude of solar cycle 24 based on a new precursor method

2010 ◽  
Vol 28 (2) ◽  
pp. 417-425 ◽  
Author(s):  
A. Yoshida ◽  
H. Yamagishi
Keyword(s):  
Magnetic Field ◽  
Solar Cycle ◽  
Solar Minimum ◽  
Physical Phenomenon ◽  
Late Phase ◽  
The Sun ◽  
Precursor Method ◽  
Solar Cycle 24 ◽  
Cycle 24 ◽  
The Imf

Abstract. It is shown that the monthly smoothed sunspot number (SSN) or its rate of decrease during the final years of a solar cycle is correlated with the amplitude of the succeeding cycle. Based on this relationship, the amplitude of solar cycle 24 is predicted to be 84.5±23.9, assuming that the monthly smoothed SSN reached its minimum in December 2008. It is further shown that the monthly SSN in the three-year period from 2006 through 2008 is well correlated with the monthly average of the intensity of the interplanetary magnetic field (IMF). This correlation indicates that the SSN in the final years of a solar cycle is a good proxy for the IMF, which is understood to reflect the magnetic field in the corona of the sun, and the IMF is expected to be smallest at the solar minimum. We believe that this finding illuminates a physical meaning underlying the well-known precursor method for forecasting the amplitude of the next solar cycle using the aa index at the solar minimum or its average value in the decaying phase of the solar cycle (e.g. Ohl, 1966), since it is known that the geomagnetic disturbance depends strongly on the intensity of the IMF. That is, the old empirical method is considered to be based on the fact that the intensity of the coronal magnetic field decreases in the late phase of a solar cycle in parallel with the SSN. It seems that the precursor method proposed by Schatten et al. (1978) and Svalgaard et al. (2005), which uses the intensity of the polar magnetic field of the sun several years before a solar minimum, is also based on the same physical phenomenon, but seen from a different angle.

scholarly journals Probable Value for the Next Sunspot Minimum

2014 ◽  
Vol 2014 ◽  
pp. 1-4
Author(s):  
Virginia Mabel Silbergleit
Keyword(s):  
Solar Cycle ◽  
Solar Minimum ◽  
The Sun ◽  
Solar Cycles ◽  
Additional Insight ◽  
Sunspot Minimum ◽  
Sunspot Numbers ◽  
Solar Cycle 24 ◽  
Cycle 24

Gumbel’s first distribution is applied to smoothed monthly mean sunspot numbers for solar cycles 10 to 24. According to that, the next minimum for solar cycle 24-25 transition would be the deepest solar minimum of the last 150 years. This study provides an additional insight about changes in the Sun which are currently happening.

scholarly journals Earth-affecting solar transients: a review of progresses in solar cycle 24

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Jie Zhang ◽  
Manuela Temmer ◽  
Nat Gopalswamy ◽  
Olga Malandraki ◽  
Nariaki V. Nitta ◽  
...  
Keyword(s):  
Solar Cycle ◽  
Solar Energetic Particle ◽  
Space Environment ◽  
Energy Output ◽  
Human Society ◽  
The Sun ◽  
Efficient Manner ◽  
Solar Cycle 24 ◽  
Interaction Regions ◽  
Cycle 24

AbstractThis review article summarizes the advancement in the studies of Earth-affecting solar transients in the last decade that encompasses most of solar cycle 24. It is a part of the effort of the International Study of Earth-affecting Solar Transients (ISEST) project, sponsored by the SCOSTEP/VarSITI program (2014–2018). The Sun-Earth is an integrated physical system in which the space environment of the Earth sustains continuous influence from mass, magnetic field, and radiation energy output of the Sun in varying timescales from minutes to millennium. This article addresses short timescale events, from minutes to days that directly cause transient disturbances in the Earth’s space environment and generate intense adverse effects on advanced technological systems of human society. Such transient events largely fall into the following four types: (1) solar flares, (2) coronal mass ejections (CMEs) including their interplanetary counterparts ICMEs, (3) solar energetic particle (SEP) events, and (4) stream interaction regions (SIRs) including corotating interaction regions (CIRs). In the last decade, the unprecedented multi-viewpoint observations of the Sun from space, enabled by STEREO Ahead/Behind spacecraft in combination with a suite of observatories along the Sun-Earth lines, have provided much more accurate and global measurements of the size, speed, propagation direction, and morphology of CMEs in both 3D and over a large volume in the heliosphere. Many CMEs, fast ones, in particular, can be clearly characterized as a two-front (shock front plus ejecta front) and three-part (bright ejecta front, dark cavity, and bright core) structure. Drag-based kinematic models of CMEs are developed to interpret CME propagation in the heliosphere and are applied to predict their arrival times at 1 AU in an efficient manner. Several advanced MHD models have been developed to simulate realistic CME events from the initiation on the Sun until their arrival at 1 AU. Much progress has been made on detailed kinematic and dynamic behaviors of CMEs, including non-radial motion, rotation and deformation of CMEs, CME-CME interaction, and stealth CMEs and problematic ICMEs. The knowledge about SEPs has also been significantly improved. An outlook of how to address critical issues related to Earth-affecting solar transients concludes this article.

scholarly journals Proton activity of the Sun in current solar cycle 24

2015 ◽  
Vol 15 (7) ◽  
pp. 1036-1044 ◽  
Author(s):  
Chuan Li ◽  
Leonty I. Miroshnichenko ◽  
Cheng Fang
Keyword(s):  
Solar Cycle ◽  
The Sun ◽  
Solar Cycle 24 ◽  
Proton Activity ◽  
Cycle 24

scholarly journals Lessons learned from predictions of Solar Cycle 24

2020 ◽  
Vol 10 ◽  
pp. 60
Author(s):  
W. Dean Pesnell
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Coronal Mass Ejections ◽  
Sunspot Cycle ◽  
Lessons Learned ◽  
Machine Learning Techniques ◽  
Polar Regions ◽  
The Sun ◽  
Solar Cycle 24 ◽  
Cycle 24

Solar Cycle 24 has almost faded and the activity of Solar Cycle 25 is appearing. We have learned much about predicting solar activity in Solar Cycle 24, especially with the data provided by SDO and STEREO. Many advances have come in the short-term predictions of solar flares and coronal mass ejections, which have benefited from applying machine learning techniques to the new data. The arrival times of coronal mass ejections is a mid-range prediction whose accuracy has been improving, mostly due to a steady flow of data from SoHO, STEREO, and SDO. Longer term (greater than a year) predictions of solar activity have benefited from helioseismic studies of the plasma flows in the Sun. While these studies have complicated the dynamo models by introducing more complex internal flow patterns, the models should become more robust with the added information. But predictions made long before a sunspot cycle begins still rely on precursors. The success of some categories of the predictions of Solar Cycle 24 will be examined. The predictions in successful categories should be emphasized in future work. The SODA polar field precursor method, which has accurately predicted the last three cycles, is shown for Solar Cycle 25. Shape functions for the sunspot number and F10.7 are presented. What type of data is needed to better understand the polar regions of the Sun, the source of the most accurate precursor of long-term solar activity, will be discussed.

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