HR: 1340h
AN: SH23A-1169    [Abstracts]
TI: Temporal Intermittency with Spatially Coherent Rolls in 2D Boussinesq Magnetoconvection
AU: * Bekki, N
EM: bekki@ge.ce.nihon-u.ac.jp
AF: Nihon University, College og Engineering, Koriyama,Fukushima, 963-8642, Japan
AU: Kiyono, K
EM: kiyono@ge.ce.nihon-u.ac.jp
AF: Nihon University, College og Engineering, Koriyama,Fukushima, 963-8642, Japan
AU: Konno, H
EM: hkonnp@sakura.cc.tsukuba.ac.jp
AB: We study a two-dimensional Boussinesq magnetoconvection numerically in order to make clear the difference between spatial and temporal intermittency of stochastic fluctuations near the critical bifurcation point. In this system, a temporal intermittent chaos with spatially coherent rolls is observed near the bifurcation point due to nonlinear interaction between magnetic fields and plasma convection like in the solar convection zone. To characterize the temporal intermittency, introducing a simple multiplicative stochastic model, we analyze the scale dependence of the probability density function (PDF) with an increasing coarse-grained scale of the time series. This approach has been introduced originally to study the intermittency problem of hydrodynamic turbulence. In our system, the PDF's near the critical bifurcation point display strongly non-Gaussian properties, specifying highly clustered intermittent behaviors of magnetic fluctuations. In addition, we find that the intermittent fluctuations near the bifurcation point show very slow convergence to a Gaussian similar to the Kolmogorov- Obukhov scenario for fully developed spatiotemporal turbulence, and that there exists a scaling law in the behavior of the non-Gaussian parameter as a function of the coarse-grained scale. We expect that our analysis method is applicable to the intermittent behavior of solar observational data and to the nonlinear generation of stochastic variable.
DE: 7524 Magnetic fields
DE: 7805 Chaos (4420)
DE: 7839 Nonlinear phenomena (4400, 6944)
DE: 7857 Stochastic phenomena (3235, 3265, 4475)
DE: 7863 Turbulence (4490)
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting