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Beer, Jürg; Tobias, Steven M.; Weiss, N. O.

doi:10.1023/a:1005026001784

Cited by 380 publications

(194 citation statements)

References 27 publications

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“…1 suggests that the solar dipole field essentially disappeared? The concentration of 10 Be in ice cores suggests that it did (Beer et al, 1998;Berggren et al, 2009), while the auroral record (Siscoe, 1980) indicates a general diminution in solar wind activity during this time. Can the "minimal solar activity" of Schrijver et al (2011) maintain a solar wind in the absence of the solar polar fields and, if so, would that solar wind be primarily slow solar wind?…”

Section: Questionsmentioning

confidence: 92%

The floor in the solar wind: status report

Cliver

2011

Proc. IAU

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Abstract. Cliver & Ling (2010) recently suggested that the solar wind had a floor or groundstate magnetic field strength at Earth of ∼2.8 nT and that the source of the field was the slow solar wind. This picture has recently been given impetus by the evidence presented by Schrijver et al. (2011) that the Sun has a minimal magnetic state that was approached globally in 2009, a year in which Earth was imbedded in slow solar wind ∼70% of the time. A precursor relation between the solar dipole field strength at solar minimum and the peak sunspot number (SSN M A X ) of the subsequent 11-yr cycle suggests that during Maunder-type minima (when SSNM A X was ∼0), the solar polar field strength approaches zero -indicating weak or absent polar coronal holes and an increase to nearly ∼100% in the time that Earth spends in slow solar wind.

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Section: Questionsmentioning

confidence: 92%

The floor in the solar wind: status report

Cliver

2011

Proc. IAU

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“…Generalizing from these results, it is apparent that oscillatory dynamos must involve a multiplicity of patterns, only a few of which are stable. Relevant behaviour has been demonstrated in an idealized nonlinear Cartesian model, governed by partial differential equations (Beer, Tobias & Weiss 1998;Knobloch, Tobias & Weiss 1998;Arlt & Weiss 2014). The complicated nonlinear oscillations arise owing to the quadratic back reaction of the Lorentz force on differential rotation in the model -a deterministic process.…”

Section: Symmetry Properties Of Deterministic Models Governed By Diffmentioning

confidence: 99%

Supermodulation of the Sun's magnetic activity: the effects of symmetry changes

Weiss¹,

Tobias²

2015

Mon. Not. R. Astron. Soc.

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In this paper we argue that the solar activity record, as revealed by telescopic observations and proxy data from the abundances of cosmogenic isotopes, is consistent with the action of a deterministic nonlinear chaotic dynamo. In particular we claim that the long timescale 'super-modulation' apparent in the isotopic record can be ascribed to switching of the dynamo between two different modulational patterns. The first (which is currently in operation) involves deep grand minima and occasional changes in symmetry triggered by these minima. The second, which exhibits only weak modulation and no grand minima, arises as a consequence of symmetry breaking. These processes are demonstrated for highly idealized simple models of the nonlinear dynamo equations.

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“…The sunspot number is not a good indicator at low solar magnetic activity: during the so-called Maunder Minimum the sunspot number shows almost no activity, whereas the 14 C production rate shows solar modulation . This was explained in Beer et al (1998) by the fact that during the Maunder Minimum strong toroidal magnetic flux tubes (sunspots) were absent but weak ephemeral magnetic field (also indicated by the 14 C production rate) were present.…”

Section: The Solar Dynamomentioning

confidence: 99%

Solar Weather Event Modelling and Prediction

et al. 2009

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Key drivers of solar weather and mid-term solar weather are reviewed by considering a selection of relevant physics-and statistics-based scientific models as well as a selection of related prediction models, in order to provide an updated operational scenario for space weather applications. The characteristics and outcomes of the considered scientific and prediction models indicate that they only partially cope with the complex nature of solar activity for the lack of a detailed knowledge of the underlying physics. This is indicated by the fact that, on one hand, scientific models based on chaos theory and non-linear dynamics reproduce better the observed features, and, on the other hand, that prediction models based on statistics and artificial neural networks perform better. To date, the solar weather prediction success at most time and spatial scales is far from being satisfactory, but the forthcoming ground-and space-based high-resolution observations can add fundamental tiles to the modelling and predicting frameworks as well as the application of advanced mathematical approaches in the analysis of diachronic solar observations, that are a must to provide comprehensive and homogeneous data sets.

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Untitled

Cited by 380 publications

References 27 publications

The floor in the solar wind: status report

The floor in the solar wind: status report

Supermodulation of the Sun's magnetic activity: the effects of symmetry changes

Solar Weather Event Modelling and Prediction

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