The Gleissberg cycle by a nonlinear αΛ dynamo
نویسنده
چکیده
This paper suggests a numerical model of the Gleissberg cycle based on a spherical shell dynamo. The formulation of the problem includes a description both of the rotation law and of the hydromagnetic dynamo. The suggested model allows the Gleissberg cycle to be interpreted as resulting from the magnetic feedback on the angular momentum fluxes which maintain the rotation law in the shell. The period of the long-term variations is determined by relaxation properties of the shell. Hence, it is directly associated with the time taken to re-establish the differential rotation after the magnetic perturbations of the angular momentum transport.
منابع مشابه
A&a Manuscript No. Cycle times and Magnetic Amplitudes in Nonlinear 1d 2 -dynamos
A nonlinear, 1D-slab, 2-dynamo is analysed for magnetic eld amplitudes and for the relation between the cycle time and the dynamo number. If the only nonlin-earity is the conventional-quenching, the magnetic eld strongly grows with the dynamo number, while the dependence of the cycle time is only rather weak. The opposite is true if the nonlinear feedback is more consistently included: the comp...
متن کاملPeriodic magnetorotational dynamo action as a prototype of nonlinear magnetic-field generation in shear flows.
The nature of dynamo action in shear flows prone to magnetohydrodynamc instabilities is investigated using the magnetorotational dynamo in Keplerian shear flow as a prototype problem. Using direct numerical simulations and Newton's method, we compute an exact time-periodic magnetorotational dynamo solution to three-dimensional dissipative incompressible magnetohydrodynamic equations with rotati...
متن کاملSolar cosmic ray events for the period 15611994 2. The Gleissberg periodicity
A total of 125 large fluence solar proton events identified from the nitrate deposition in ice core from Greenland for the period 1561-1950 are examined in an exploratory study of the geophysical information that will be available from such data in the future. These data have been augmented with ionospheric and satellite data for the period 1950-1994. There were five periods in the vicinity of ...
متن کاملVariations of the solar cycle profile in a solar dynamo with fluctuating dynamo governing parameters
Context. Solar cycles vary in their amplitude and shape. There are several empirical relations between various parameters linking cycle’s shape and amplitude, in particular the Waldmeier relations. Aims. As solar cycle is believed to be a result of the solar dynamo action, these relations require explanation in the framework of this theory. Here we aim to present a possible explanation of such ...
متن کاملLong-term changes in the cosmic ray intensity at Earth, 1428–2005
[1] The instrumental cosmic ray data recorded in the interval 1933–1965 by S. E. Forbush and H. V. Neher and cosmogenic Be data are merged with the neutron monitor data since 1951 to study the longand short-term variations in the galactic cosmic radiation intensity for the interval 1428–2005. It is shown that the ionization chamber data published by S. E. Forbush were deliberately detrended to ...
متن کامل