Another Mini Solar Maximum in the Offing: A Prediction for the Amplitude of Solar Cycle 25

Janardhan, P.; Ananthakrishnan, S.

doi:10.1029/2019ja027508

Cited by 18 publications

(10 citation statements)

References 46 publications

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“…This is in good agreement with the amplitude estimated using SLD. Our predicted amplitude of sunspot number 99.13 ± 14.97 for cycle 25 is in agreement with the recent predictions made by few other investigators (within the range of 82-140); (Upton & Hathaway 2018;Bhowmik & Nandy 2018;Petrovay et al 2018;Bisoi et al 2020;Sello 2019;Dani & Sulistiani 2019;Covas et al 2019;Labonville et al 2019;Miao et al 2020). On the other hand, some studies (Sarp et al 2018;Li et al 2018) contrarily predict the cycle 25 to have a higher value .…”

Section: Discussionsupporting

confidence: 92%

Spotless days and geomagnetic index as the predictors of solar cycle 25

Burud,

Jain,

Awasthi

et al. 2021

Preprint

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We study the sunspot activity in relation to spotless days (SLDs) during the descending phase of solar cycle 11-24 to predict the amplitude of sunspot cycle 25. For this purpose, in addition to SLD, we also use the geomagnetic activity (aa index) during the descending phase of a given cycle. A very strong correlation of the SLD (R=0.68) and aa index (R=0.86) during the descending phase of a given cycle with the maximum amplitude of next solar cycle has been estimated.The empirical relationship led us to deduce the amplitude of cycle 25 to be 99.13± 14.97 and 104.23± 17.35 using SLD and aa index, respectively as predictors.Both the predictors provide comparable amplitude for solar cycle 25 and reveal that the solar cycle 25 will be weaker than cycle 24. Further we derive that the maximum of cycle 25 is likely to occur between February and March 2024. While the aa index has been used extensively in the past, this work establishes SLDs as another potential candidate for predicting the characteristics of the next cycle.

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Section: Discussionsupporting

confidence: 92%

Spotless days and geomagnetic index as the predictors of solar cycle 25

Burud,

Jain,

Awasthi

et al. 2021

Preprint

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“…A noticeable decrease in magnetospheric activity and other manifestations of space weather is associated with this fact and a decrease in the number and intensity of interplanetary manifestations of CME. Since all measurements were carried out in the ecliptic plane, the observed fact can be explained not only by a decrease in the global activity of the Sun, but also by a change in the location of various types of solar wind sources at relatively low and high solar latitudes (e.g., Bisoi et al., 2020) which usually occurs when the direction of the solar global magnetic field changes in the solar cycle.…”

Section: Discussionmentioning

confidence: 99%

Drop of Solar Wind at the End of the 20th Century

et al. 2021

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Variations in the solar wind (SW) parameters with scales of several years are an important characteristic of solar activity and the basis for a long‐term space weather forecast. We examine the behavior of interplanetary parameters over 21–24 solar cycles (SCs) on the basis of the OMNI database (https://spdf.gsfc.nasa.gov/pub/data/omni). Since changes in the parameters can be associated with both changes in the number of different large‐scale types of SW and with variations in the values of these parameters at different phases of the solar cycle and during the transition from one cycle to another, we select the entire study period in accordance with the Catalog of large‐scale SW types for 1976–2019 (see the site http://www.iki.rssi.ru/pub/omni, [Yermolaev, Nikolaeva, et al., 2009, https://doi.org/10.1134/s0010952509020014], which covers the period from 21 to 24 SCs) and in accordance with the phases of the cycles, and average the parameters at selected intervals. In addition to a sharp drop in the number of interplanetary coronal mass ejections and associated sheath types, there is a noticeable drop in the value (by 20%–40%) of plasma parameters and magnetic field in different types of solar wind at the end of the 20th century and a continuation of the fall or persistence at a low level in the 23–24 cycles. Such a drop in the solar wind is apparently associated with a decrease in solar activity and manifests itself in a noticeable decrease in space weather factors.

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“…Solar cycle 23 began in August 1996 and ended in December 2008 with its maximum around 2002 (Joselyn et al, 1997;Temmer et al, 2006). Following the minimum of cycle 23, solar cycle 24 began in December 2008 and ended in December 2019 reaching its maximum around mid of 2014 (Pesnell, 2008;Bisoi et al, 2020). Cycle 24 is found to be weaker than the previous cycle in terms of disturbances that appeared on the solar surface and in the heliosphere (Antia and Basu, 2010;Richardson, 2013).…”

Section: Introductionmentioning

confidence: 87%

Radial Sizes and Expansion Behavior of ICMEs in Solar Cycles 23 and 24

Mishra

Doshi

Srivastava

2021

Front. Astron. Space Sci.

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We attempt to understand the influence of the heliospheric state on the expansion behavior of coronal mass ejections (CMEs) and their interplanetary counterparts (ICMEs) in solar cycles 23 and 24. Our study focuses on the distributions of the radial sizes and duration of ICMEs, their sheaths, and magnetic clouds (MCs). We find that the average radial size of ICMEs (MCs) at 1 AU in cycle 24 is decreased by ∼33% (∼24%) of its value in cycle 23. This is unexpected as the reduced total pressure in cycle 24 should have allowed the ICMEs in cycle 24 to expand considerably to larger sizes at 1 AU. To understand this, we study the evolution of radial expansion speeds of CME-MC pairs between the Sun and Earth based on their remote and in situ observations. We find that radial expansion speeds of MCs at 1 AU in solar cycles 23 and 24 are only 9 and 6%, respectively, of their radial propagation speeds. Also, the fraction of radial propagation speeds as expansion speeds of CMEs close to the Sun are not considerably different between solar cycles 23 and 24. We also find a constant (0.63 ± 0.1) dimensionless expansion parameter of MCs at 1 AU for both solar cycles 23 and 24. We suggest that the reduced heliospheric pressure in cycle 24 is compensated by the reduced magnetic content inside CMEs/MCs, which did not allow the CMEs/MCs to expand enough in the later phase of their propagation. Furthermore, the average radial sizes of sheaths are the same in both cycles, which is unexpected, given the weaker CMEs/ICMEs in cycle 24. We discuss the possible causes and consequences of our findings relevant for future studies.

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Another Mini Solar Maximum in the Offing: A Prediction for the Amplitude of Solar Cycle 25

Cited by 18 publications

References 46 publications

Spotless days and geomagnetic index as the predictors of solar cycle 25

Spotless days and geomagnetic index as the predictors of solar cycle 25

Drop of Solar Wind at the End of the 20th Century

Radial Sizes and Expansion Behavior of ICMEs in Solar Cycles 23 and 24

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