Turbulent magnetic pressure instability in stratified turbulence
نویسندگان
چکیده
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 of interest is conducted in order to clarify this apparent discrepancy.
منابع مشابه
Spontaneous Formation of Magnetic Flux Concentrations in Stratified Turbulence
The negative effective magnetic pressure instability discovered recently in direct numerical simulations (DNSs) may play a crucial role in the formation of sunspots and active regions in the Sun and stars. This instability is caused by a negative contribution of turbulence to the effective mean Lorentz force (the sum of turbulent and non-turbulent contributions) and results in the formation of ...
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 کاملEffect of Stratified Turbulence on Magnetic Flux Concentrations
According to conventional view, sunspots form when coherent magnetic flux tubes intersect the surface. Such tubes would rise from the bottom of the convection zone as a result of an instability. In this study an alternative view is advanced where the field is produced throughout the entire convection zone and sunspots may form from local flux concentrations near the surface. In order to underst...
متن کاملEffect of Stratified Turbulence on Magnetic Flux Concentrations
According to conventional view, sunspots form when coherent magnetic flux tubes intersect the surface. Such tubes would rise from the bottom of the convection zone as a result of an instability. In this study an alternative view is advanced where the field is produced throughout the entire convection zone and sunspots may form from local flux concentrations near the surface. In order to underst...
متن کاملSelf-assembly of Shallow Magnetic Spots through Strongly Stratified Turbulence
In developed turbulence, the effective magnetic pressure of a large-scale field (non-turbulent plus turbulent contributions) can become negative. This is known to lead to a large-scale instability in strongly stratified turbulence that produces spontaneous magnetic flux concentrations. Previous studies using a horizontal magnetic field resulted in elongated field concentrations with a strength ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2011