Schwabe, Gleissberg, Suess-de Vries: Towards a consistent model of planetary synchronization of solar cycles (1910.10383v3)

Abstract: Aiming at a consistent planetary synchronization model of both short-term and long-term solar cycles, we start with an analysis of Schove's historical data of cycle maxima. Their deviations (residuals) from the average cycle duration of 11.07 years show a high degree of regularity, comprising a dominant 200-year period (Suess-de Vries cycle), and a few periods around 100 years (Gleissberg cycle). Encouraged by their robustness, we support previous forecasts of an upcoming grand minimum in the 21st century. To explain the long-term cycles, we enhance our tidally synchronized solar dynamo model by a modulation of the field storage capacity of the tachocline with the orbital angular momentum of the Sun, which is dominated by the 19.86-year periodicity of the Jupiter-Saturn synodes. This modulation of the 22.14 years Hale cycle leads to a 193-year beat period of dynamo activity which is indeed close to the Suess-de Vries cycle. For stronger dynamo modulation, the model produces additional peaks at typical Gleissberg frequencies, which seem to be explainable by the non-linearities of the basic beat process, leading to a bi-modality of the Schwabe cycle. However, a complementary role of beat periods between the Schwabe cycle and the Jupiter-Uranus/Neptune synodic cycles cannot be completely excluded.

• The paper presents a model integrating tidal synchronization with solar dynamics to explain both short- and long-term cycle variations.
• It employs wavelet and Lomb-Scargle analyses on historical solar data to identify key periodicities including the 11.07-year, 100-year, and 200-year cycles.
• The model’s modulation mechanism, influenced by solar orbital angular momentum, offers insights for predicting a potential grand solar minimum in the 21st century.

Analysis of Planetary Synchronization of Solar Cycles

The paper under consideration explores the challenging and intricate topic of planetary synchronization and its effect on solar cycles, focusing on contributions ranging from the Schwabe cycle to significant long-term cycles such as the Suess-de Vries cycle. This comprehensive paper by Stefani et al. aims to develop a consistent model that accounts for both short and long-term solar cycles, ultimately enhancing the predictive capacity related to solar activity.

The researchers employ a historical analysis of Schove's solar cycle maxima data. They report a notable conformity with a typical cycle duration of 11.07 years, prominently featuring a 200-year Suess-de Vries cycle and periods reminiscent of the Gleissberg cycle at approximately 100 years. Utilizing methodologies such as wavelet and Lomb-Scargle analyses, the authors reveal significant modulations and predict the prospect of a grand solar minimum within the 21st century.

Building on these foundational analyses, the authors enhance their solar dynamo model by incorporating tidal synchronization mechanisms. The introduction of a modulation factor tied to the solar tachocline's field storage capacity—regulated by the Sun's orbital angular momentum—adds depth to the model. This particular modulation is primarily influenced by the synodic cycle of Jupiter and Saturn, with a period of 19.86 years. In this framework, the interaction with the Hale cycle results in a beat period proximate to the 193 years observed for the Suess-de Vries cycle.

Notably, the model also accounts for the Schwabe cycle's potential dual-mode signature through non-linear beat processes, thus addressing the bimodal histogram feature related to cycle duration. Although the paper focuses on tidal synchronization, it acknowledges the plausibility of additional beat periods, such as those emerging from the Schwabe cycle's interaction with Jupiter-Uranus and Jupiter-Neptune synodic cycles, offering an explanation for observed Gleissberg frequencies.

While the research is compelling in its statistical and historical scope, it is also frank about ongoing uncertainties, especially concerning the exact mechanisms of spin-orbit coupling. This modulation process requires further exploration, as it hypothetically integrates a fraction of the Sun’s angular momentum into differentiable solar internal motions.

The implications of this research are manifold. Practically, it augments our ability to anticipate solar activity fluctuations, which carry profound consequences for understanding climate dynamics and calibrating technological systems exposed to solar phenomena. Theoretically, this work integrates planetary synchronization into solar dynamics models, potentially catalyzing advancements in the broader comprehension of cosmic interactions.

Future investigations are encouraged to deeply explore the identified synchronization mechanisms, perhaps incorporating more sophisticated modeling techniques to articulate further the physical underpinnings of these solar and planetary interactions. As we build on these insights, one can anticipate an era of refined solar predictability which could substantially influence both scientific inquiry and practical applications globally.