2004/02/29 by Sergei Fedotov, Irina Bashkirtseva, Lev Ryashko
Biochemistry, Genetics and Molecular Biology · Engineering · Physics and Astronomy · #Fluid Dynamics and Turbulent Flows #Geomagnetism and Paleomagnetism Studies #Solar and Space Plasma Dynamics #astro-ph
paper · pdf · doi:10.1016/j.physa.2004.05.084
21pages,7 figures
arxiv created 2004/05/01 · openalex publication_date 2004/06/29 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present and analyze a simplified stochastic αΩ-dynamo model which is designed to assess the influence of additive and multiplicative noises, non-normality of dynamo equation, and nonlinearity of the α-% effect and turbulent diffusivity, on the generation of a large-scale magnetic field in the subcritical case. Our model incorporates random fluctuations in the α-parameter and additive noise arising from the small-scale fluctuations of magnetic and turbulent velocity fields. We show that the noise effects along with non-normality can lead to the stochastic amplification of the magnetic field even in the subcritical case. The criteria for the stochastic instability during the early kinematic stage are established and the critical value for the intensity of multiplicative noise due to α-fluctuations is found. We obtain numerical solutions of non-linear stochastic differential equations and find the series of phase transitions induced by random fluctuations in the α-parameter.