Another Mini Solar Maximum in the Offing: A Prediction for the Amplitude of Solar Cycle 25 (1910.03841v1)

Abstract: We examine the temporal changes in both solar polar magnetic field (PMF) at latitudes $\ge$ $45^{\circ}$ and heliospheric magnetic field (HMF) at 1 AU during solar cycles 21--24 with emphasis on the recent activity changes after July 2015, the so called "mini solar maximum" of cycle 24. While unsigned PMF shows a solar-cycle-like variation in cycles 21 and 22, it shows an anti-solar-cycle-like variation in cycle 24. In addition, the floor level of the HMF (of 4.6 nT), i.e. the value that the HMF returns to at each solar minimum, is breached about two years prior to cycle 24 minimum, indicating a reduced HMF floor level in the upcoming cycle 24 minimum. In light of the change of unsigned PMF and the availability of a revised smoothed sunspot number (SSN) after July 2015, we have revisited the correlation of unsigned PMF and HMF at solar minimum. The correlation is used to estimate a new value of the HMF of 4.16$\pm$0.6 nT at the cycle 24 minimum and the amplitude of the upcoming cycle 25. The updated prediction is 82$\pm$8 and 133$\pm$11, on the original (V1.0) and revised (V2.0) SSN scales, respectively. These better and more reliable SSN values (due to the larger data set) imply that we will witness another mini solar maximum in the upcoming cycle 25 which will be relatively stronger than cycle 24 and a little weaker than cycle 23, even if the current solar cycle minimum occurs in 2021 instead of 2020.

• The paper presents an empirical prediction of Solar Cycle 25’s sunspot number, identifying SSN maxima of 82±8 and 133±11 on two scales.
• It analyzes transitions in solar polar magnetic fields, highlighting a shift from solar-cycle-like to anti-solar-cycle variations during Cycle 24.
• The study revisits the heliospheric magnetic field floor level, suggesting reduced solar magnetic activity with significant implications for space weather forecasting.

Prediction for the Amplitude of Solar Cycle 25

The paper "Another Mini Solar Maximum in the Offing: A Prediction for the Amplitude of Solar Cycle 25" by Susanta Kumar Bisoi et al. presents an empirical analysis of solar polar magnetic fields (PMF) and heliospheric magnetic fields (HMF) to predict the properties of the forthcoming Solar Cycle 25. This prediction is crucial for understanding solar activity's impact on space weather, which has practical implications for satellite operations and space missions.

The authors identify a transition in the behavior of unsigned solar polar magnetic fields, which exhibit an anti-solar-cycle-like variation in Solar Cycle 24, deviating from the solar-cycle-like patterns observed in Cycles 21 and 22. This transition is crucial as it suggests differences in the solar dynamo processes influencing solar magnetic fields. The unsigned PMF shows a steady decline in field strength starting in the mid-1990s, only to unexpectedly increase in 2015, reflecting complex changes in the solar magnetic environment.

The paper further revisits the HMF floor level at the solar minimum of Cycle 24, predicting a reduced floor level compared to previous cycles. This lower floor level is indicative of an overall reduction in solar magnetic activity, aligning with the weakened solar cycles observed over recent decades.

Based on these insights, the authors provide predictions for the amplitude of Solar Cycle 25 using both the original (V1.0) and revised (V2.0) sunspot number (SSN) scales. They predict SSN maxima of 82±8 and 133±11, respectively, indicating a stronger solar cycle than Cycle 24 and suggesting another "mini solar maximum." The prediction remains consistent even if the Cycle 24 minimum is delayed to 2021.

The implications of these findings suggest that despite a trend towards diminishing solar activity, Cycle 25 could present higher solar activity than observed in Cycle 24. This holds significant implications for forecasting solar influences on space weather, necessitating updates in operational planning for current and future space missions.

Looking toward future developments, this paper highlights the potential for improved solar cycle predictions using more refined data and advanced computational models. Understanding the dynamo processes and mechanisms generating these magnetic fields could further elucidate the complexities of solar cycle dynamics.

In summary, the research provides a nuanced prediction of Solar Cycle 25's amplitude, reflecting the intricate and evolving solar magnetic field's dynamics and their broader implications for space weather forecasting and scientific inquiry.