Negative effective magnetic pressure in turbulent convection
نویسندگان
چکیده
منابع مشابه
Magnetic flux concentrations from turbulent stratified convection
Context. The formation of magnetic flux concentrations within the solar convection zone leading to sunspot formation is unexplained. Aims. We study the self-organization of initially uniform sub-equipartition magnetic fields by highly stratified turbulent convection. Methods. We perform simulations of magnetoconvection in Cartesian domains representing the uppermost 8.5−24 Mm of the solar conve...
متن کاملNon-uniformity effects in the negative effective magnetic pressure instability
In direct numerical simulations of strongly stratified turbulence we have previously studied the development of large scale magnetic structures starting from a uniform background field. This is caused by an instability resulting from a negative contribution of small-scale turbulence to the effective (mean-field) magnetic pressure, and was qualitatively reproduced in mean-field simulations (MFS)...
متن کاملProperties of the negative effective magnetic pressure instability
As was demonstrated in earlier studies, turbulence can result in a negative contribution to the effective mean magnetic pressure, which, in turn, can cause a large-scale instability. In this study, hydromagnetic mean-field modelling is performed for an isothermally stratified layer in the presence of a horizontal magnetic field. The negative effective magnetic pressure instability (NEMPI) is co...
متن کاملActive Region Formation through the Negative Effective Magnetic Pressure Instability
The negative effective magnetic-pressure instability operates on scales encompassing many turbulent eddies, which correspond to convection cells in the Sun. This instability is discussed here in connection with the formation of active regions near the surface layers of the Sun. This instability is related to the negative contribution of turbulence to the mean magnetic pressure that causes the f...
متن کاملTurbulent magnetic pressure instability in stratified turbulence
A reduction of total mean turbulent pressure due to the presence of magnetic fields was previously shown to be a measurable effect in direct numerical simulations. However, in the studied parameter regime the formation of large-scale structures, as anticipated from earlier mean-field simulations, was not found. An analysis of the relevant mean-field parameter dependency and the parameter domain...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 2012
ISSN: 0035-8711
DOI: 10.1111/j.1365-2966.2012.20801.x