Oscillator models of the solar cycle and the Waldmeier effect

M. Nagy, K. Petrovay

Research output: Contribution to journalArticle

2 Citations (Scopus)


We study the behaviour of the van der Pol oscillator when either its damping parameter μ or its nonlinearity parameter ξ is subject to additive or multiplicative random noise. Assuming various power law exponents for the relation between the oscillating variable and the sunspot number, for each case we map the parameter plane defined by the amplitude and the correlation time of the perturbation and mark the parameter regime where the sunspot number displays solar-like behaviour. Solar-like behaviour is defined here as a good correlation between the rise rate and cycle amplitude and the lack of a good correlation between the decay rate and amplitude, together with significant (≳10%) r.m.s. variation in cycle lengths and cycle amplitudes. It is found that perturbing μ alone the perturbed van der Pol oscillator does not show solar-like behaviour. When the perturbed variable is ξ, solar-like behaviour is displayed for perturbations with a correlation time of about 3-4 years and significant amplitude. Such studies may provide useful constraints on solar dynamo models and their parameters.

Original languageEnglish
Pages (from-to)964-967
Number of pages4
JournalAstronomische Nachrichten
Issue number9
Publication statusPublished - Nov 1 2013



  • Sun: magnetic fields
  • Sunspots

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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