A mean field dynamo from negative eddy diffusivity
نویسندگان
چکیده
منابع مشابه
Small-scale magnetic helicity losses from a mean-field dynamo
Using mean-field models with a dynamical quenching formalism, we show that in finite domains magnetic helicity fluxes associated with small-scale magnetic fields are able to alleviate catastrophic quenching. We consider fluxes that result from advection by a mean flow, the turbulent mixing down the gradient of mean small-scale magnetic helicity density or the explicit removal which may be assoc...
متن کاملMixed-parity Solutions in a Mean-field Dynamo Model
S u m m a r y : We consider the effect of including both dipole and quadrupole parities in the previous mean-field model of Hollerbach and Jones (1995), which considered dipole parity only. Allowing for both parities, we find that the onset of dynamo action occurs at a0 « 6, in the form of a purely quadrupolar dynamo wave. A symmetry-breaking bifurcation then occurs at ao « 11, beyond which the...
متن کاملZonal flows in a mean-field solar dynamo model
Cyclic variations are observed in the solar differential rotation profile. The 11 year periodicity of these zonal shear flows (often referred to as “torsional oscillations”) is consistent with the idea that they are driven by the Lorentz forces that are associated with the large-scale solar dynamo. This suggests that these flows may be able to provide indirect observational evidence that can be...
متن کاملNon-linear magnetic diffusivity in mean-field electrodynamics
AB S TRACT We consider non-linear transport and drift processes caused by an inhomogeneous magnetic field in a turbulent fluid. The coefficients of magnetic diffusivity and drift velocity are calculated by making use of the second-order correlation approximation. Transport processes in the presence of a sufficiently strong magnetic field become anisotropic with larger diffusion rate and turbule...
متن کاملMean-field helicity in random α-dynamo twisted flows
Recent results by Shukurov, Stepanov and Sokoloff [Phys. Rev. E 78,025301,(2008)] on dynamo action in Moebius strip flows, indicate that strong magnetic fields appear in regions where, electric current and flow kinetic helicities have the same sign. Here, an analytical version of their numerical result is obtained by a simpler method of considering the laminar non-turbulent limit, of a twisted ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 2013
ISSN: 0035-8711,1365-2966
DOI: 10.1093/mnras/stt590