Stochastic Resonance could explain Recurrence of Grand Minima

2020 ◽  
Author(s):  
Carlo Albert ◽  
Simone Ulzega
Keyword(s):  
Magnetic Field ◽  
Solar Activity ◽  
Stochastic Resonance ◽  
Intrinsic Noise ◽  
Magnetic Activity ◽  
Stable States ◽  
Frequent Switching ◽  
Solar Magnetic Activity ◽  
Stochastic Time ◽  
Grand Minima

<p>Proxies of solar activity have revealed repeated Grand Minima that occur with a certain regularity associated with the well-known Gleissberg and Süss/deVries cycles. These and other prominent cycles in the spectrum of solar activity are also seen in the spectrum of the planetary torque exerted on the solar tachocline, which has revived the hypothesis of a planetary influence on solar activity. It is not clear, however, how the extremely weak planetary forcing could influence the solar magnetic activity. Here, we suggest that stochastic resonance could explain the necessary amplification of the forcing and provide numerical evidence from stochastic time-delayed dynamo models. If the intrinsic noise of the solar dynamo allows for a frequent switching between active and quiescent stable states, tiny periodic forcings can be greatly amplified, provided the dynamo is poised close to a critical point. Such a forcing could be caused by a tidal modulation of the minimal magnetic field required for flux-tube buoyancy.</p>

scholarly journals Reflection of Solar Activity Dynamics in Radionuclide Data

Radiocarbon ◽  
1992 ◽  
Vol 34 (2) ◽  
pp. 207-212 ◽  
Author(s):  
A. V. Blinov ◽  
M. N. Kremliovskij
Keyword(s):  
Nonlinear Dynamics ◽  
Solar Activity ◽  
Numerical Methods ◽  
Chaotic Behavior ◽  
Magnetic Activity ◽  
Data Sets ◽  
Cosmogenic Nuclide ◽  
Proxy Records ◽  
Solar Magnetic Activity ◽  
Activity Dynamics

Variability of solar magnetic activity manifested within sunspot cycles demonstrates features of chaotic behavior. We have analyzed cosmogenic nuclide proxy records for the presence of the solar activity signals. We have applied numerical methods of nonlinear dynamics to the data showing the contribution of the chaotic component. We have also formulated what kind of cosmogenic nuclide data sets are needed for investigations on solar activity.

scholarly journals Sunspot cycles and Grand Minima

2009 ◽  
Vol 5 (S264) ◽  
pp. 111-119 ◽  
Author(s):  
Dmitry Sokoloff ◽  
Rainer Arlt ◽  
David Moss ◽  
Steven H. Saar ◽  
Ilya Usoskin
Keyword(s):  
Magnetic Activity ◽  
Dynamo Model ◽  
Isotopic Data ◽  
Dynamo Theory ◽  
History Of ◽  
Solar Magnetic Activity ◽  
Basic Features ◽  
Random Fluctuations ◽  
Grand Minima

AbstractObservational data concerning the long-term history of cyclic solar activity as recorded in sunspot and isotopic data are discussed in the context of solar dynamo theory. In particular, a simple dynamo model based on differential rotation and the mirror asymmetry of convection with random fluctuations of dynamo governing parameters is shown to reproduce some basic features of the solar magnetic activity evolution.

scholarly journals A model for grand minima and geomagnetic reversals

2011 ◽  
Vol 7 (S286) ◽  
pp. 360-366
Author(s):  
D. D. Sokoloff ◽  
G. S. Sobko ◽  
V. I. Trukhin ◽  
V. N. Zadkov
Keyword(s):  
Geomagnetic Field ◽  
Temporal Evolution ◽  
Physical Nature ◽  
Magnetic Activity ◽  
Qualitative Explanation ◽  
Solar Magnetic Activity ◽  
Activity Cycles ◽  
Polarity Reversals ◽  
Simple Dynamical System ◽  
Grand Minima

AbstractWe suggest a simple dynamical system which mimics a nonlinear dynamo which is able to provide (in specific domains of its parametric space) the temporal evolution of solar magnetic activity cycles as well as evolution of geomagnetic field including its polarity reversals. A qualitative explanation for the physical nature of both phenomena is presented and discussed.

scholarly journals Geomagnetic Kp Index and Planetary Magnetosphere Size Relationship: for Mercury and Jupiter During two Types of Geomagnetic Conditions

2020 ◽  
Vol 17 (3) ◽  
pp. 0806
Author(s):  
Mays M. Al-Gbory ◽  
Najat Mohamed Ameen
Keyword(s):  
Magnetic Field ◽  
Solar Activity ◽  
Solar System ◽  
Weak Magnetic Field ◽  
Geomagnetic Storms ◽  
Magnetic Activity ◽  
The Sun ◽  
Planetary Surface ◽  
Surface Magnetic Field ◽  
The Many

     Kp index correlates with the many magnetosphere properties, which are used to measure the level of magnetic activity. In the solar system, the two different planets, Mercury with weak magnetic field and Jupiter with strong magnetic field, are selected for this study to calculate the planet's magnetosphere radius (RMP) which represents the size of magnetosphere compared with solar activity through Kp index,  through two types of geomagnetic conditions; quiet and strong for the period (2016-2018). From the results, we found that there are reversible relations between them during strong geomagnetic storms, while there are direct relations during quiet geomagnetic conditions. Also it is found that there is a reduction in the size of magnetosphere during the strong geomagnetic storms as compared to the magnetosphere size during geomagnetic quiet conditions for the two planets: Mercury and Jupiter. We can conclude from these results that the relation between storm type and magnetosphere size is independent of the strength of planetary surface magnetic field and their distance from the Sun.

scholarly journals Manifestations of Solar Magnetic Fields

1998 ◽  
Vol 11 (2) ◽  
pp. 857-860
Author(s):  
S.K. Solanki
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Solar Magnetic Field ◽  
Magnetic Activity ◽  
The Sun ◽  
Solar Magnetic Fields ◽  
Quiet Sun ◽  
Solar Magnetic Activity

AbstractThe magnetism of the Sun manifests itself in innumerable ways, many of which constitute what is referred to as solar magnetic activity, while others are counted among the phenomena of the quiet Sun. After a brief overview of the structure of the solar magnetic field, a few examples of its manifestations are pointed out.

scholarly journals Global simulations of stellar dynamos

2019 ◽  
Vol 15 (S354) ◽  
pp. 65-85
Author(s):  
G. Guerrero
Keyword(s):  
Magnetic Field ◽  
Spherical Shell ◽  
Ab Initio ◽  
Open Problem ◽  
Magnetic Activity ◽  
Large Eddy Simulations ◽  
The Past ◽  
Large Eddy ◽  
Dynamo Mechanism ◽  
Solar Magnetic Activity

AbstractThe dynamo mechanism, responsible for the solar magnetic activity, is still an open problem in astrophysics. Different theories proposed to explain such phenomena have failed in reproducing the observational properties of the solar magnetism. Thus, ab-initio computational modeling of the convective dynamo in a spherical shell turns out as the best alternative to tackle this problem. In this work we review the efforts performed in global simulations over the past decades. Regarding the development and sustain of mean-flows, as well as mean magnetic field, we discuss the points of agreement and divergence between the different modeling strategies. Special attention is given to the implicit large-eddy simulations performed with the EULAG-MHD code.

scholarly journals Solar Wind Parameters and Its Geoefficiency During Minimums of Four Solar Cycles

2021 ◽  
Vol 31 (4) ◽  
pp. 508-514
Author(s):  
Vitalii Degtyarev ◽  
Georgy Popov ◽  
Svetlana Chudnenko
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Solar Activity ◽  
Geomagnetic Activity ◽  
Statistical Processing ◽  
Magnetic Activity ◽  
Solar Cycles ◽  
Deep Minimum ◽  
Significant Difference ◽  
Solar Wind Parameters

Recently a number of publications have appeared on the long and deep minimum in cycle 23 of solar activity. This interest is due to the fact that it turned out to be the longest and deepest in terms of the number of sunspots in the entire era of space exploration. The features of the minimum of cycle 23 of solar activity and the beginning of cycle 24 made it possible to assume that in the coming decades, a minimum of solar activity similar to the Dalton or Maunder minimum, leading to a global change in the earth's climate, may occur. Such assumptions make a detailed study of the influence of the minimum of solar cycle 23 on the parameters of the solar wind and the interplanetary magnetic field, as well as a comparison of this influence with similar manifestations in the three previous cycles very urgent. The work carried out statistical processing and analysis of data available in print and on the Internet on the indices of solar activity (W and F10.7), on geomagnetic activity, as well as on the parameters of the solar wind and interplanetary field. In contrast to other similar studies, when choosing time intervals for all cycles, only one — 12 months was used, which made it possible to exclude annual and semi-annual variations in solar wind parameters. For the considered minima of solar activity, the geoeffectiveness of the disturbed fluxes ICME, CIR, and Sheath was considered. A monotonic and very significant decrease in the geoeffectiveness of the ICME streams was found. Data processing on the hourly average values of the solar wind parameters at the minima of geomagnetic activity for 4 cycles confirmed the significant difference between cycle 23 and the previous ones in the behavior of the magnetic field. The cycle-by-cycle decrease in the geoeffectiveness of coronal ejections discussed in the press deserves a more detailed analysis using extensive data on magnetic activity indices.

Towards a more reliable reconstruction of the historical solar variability: a more realistic description of solar ephemeral magnetic regions

2020 ◽  
Author(s):  
Bernhard Hofer ◽  
Natalie A. Krivova ◽  
Chi-Ju Wu ◽  
Ilya A. Usoskin ◽  
Robert Cameron
Keyword(s):  
Sunspot Number ◽  
Solar Irradiance ◽  
Climate Models ◽  
Active Regions ◽  
Magnetic Activity ◽  
Maunder Minimum ◽  
Realistic Description ◽  
Solar Magnetic Activity ◽  
Grand Minima

<p>Solar irradiance is a crucial input to climate models, but its measurements are only available since 1978. The variability of solar irradiance on climate-relevant time-scales is caused by the competition between bright and dark features formed by the magnetic fields emerging on the solar surface. Thus, models have been developed that reconstruct past irradiance variability from proxies of the solar magnetic activity. The longest direct proxy is the sunspot number. The common problem of such reconstructions is, however, that while sunspots adequately describe the evolution of the active regions (ARs) (large bipolar regions hosting sunspots), the evolution of their smaller counterparts, the ephemeral regions (ERs), is not directly featured by sunspots. At the same time, these small regions are much more numerous and are believed to be the main source of the long-term irradiance changes, which are of special interest to climate models. We develop an improved description of the ephemeral region emergence taking different solar observational constraints into account. The model builds on the SATIRE-T model, in which the emergence of ARs is described by the sunspot number and the emergence of the ERs is linearly linked to that of ARs. The latter, however, implies that whenever the sunspot number drops to zero, no magnetic field emerges in the model. In the new model, the emergence of the ERs is no longer linked to sunspots linearly. Instead, ARs and ERs are considered to be parts of a single power-law size distribution of the emerging magnetic regions. This ensures that even in the absence of ARs (e.g., during the grand minima of solar activity), the emergence rate of ERs remains non-zero. In particular, the solar open magnetic flux reconstructed using this approach does not drop to zero during the Maunder minimum, in agreement with independent reconstructions from the cosmogenic isotope data. Such an improved description of the ERs will allow a better constraint on the maximum solar irradiance drop during grand minima events. This, in turn, will allow a better constraint on the potential solar forcing in the future.</p>

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