Physics
Scientific paper
Dec 2000
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000soph..197..215d&link_type=abstract
Solar Physics, v. 197, Issue 2, p. 215-226 (2000).
Physics
4
Scientific paper
The integrals, I_i(t) = ∫_GL u_i j × B_idv over the volume GL are calculated in a dynamo model of the Babcock-Leighton type studied earlier. Here, GL is the generating layer for the solar toroidal magnetic field, located at the base of the solar convection zone (SCZ); i=r, θ, φ, stands for the radial, latitudinal, and azimuthal coordinates respectively; j = (4π)^-1∇ × B, where B is the magnetic field; u_r,u_θ are the components of the meridional motion, and u_φ is the differential rotation. During a ten-year cycle the energy ∫_cycle I_φ(t)dt needs to be supplied to the azimuthal flow in the GL to compensate for the energy losses due to the Lorentz force. The calculations proceed as follows: for every time step, the maximum value of |B_φ| in the GL is computed. If this value exceeds B_cr (a prescribed field) then there is eruption of a flux tube that rises radially, and reaches the surface at a latitude corresponding to the maximum of |B_φ| (the time of rise is neglected). This flux tube generates a bipolar magnetic region, which is replaced by its equivalent axisymmetric configuration, a magnetic ring doublet. The erupted flux can be multiplied by a factor F_t, i.e., by the number of eruptions per time step. The model is marginally stable and the ensemble of eruptions acts as the source for the poloidal field. The arbitrary parameters B_cr and F_t are determined by matching the flux of a typical solar active region, and of the total erupted flux in a cycle, respectively. If E(B) is the energy, in the GL, of the toroidal magnetic field B_φ = B sin θ cos θ, B (constant), then the numerical calculations show that the energy that needs to be supplied to the differential rotation during a ten-year cycle is of the order of E(B_cr), which is considerably smaller than the kinetic energy of differential rotation in the GL. Assuming that these results can be extrapolated to larger values of B_cr, magnetic fields ~10^4 G, could be generated in the upper section of the tachocline that lies below the SCZ (designated by UT). The energy required to generate these 10^4 G fields during a cycle is of the order of the kinetic energy in the UT.
No associations
LandOfFree
The Energy Lost by Differential Rotation in the Generation of the Solar Toroidal Magnetic Field does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Energy Lost by Differential Rotation in the Generation of the Solar Toroidal Magnetic Field, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Energy Lost by Differential Rotation in the Generation of the Solar Toroidal Magnetic Field will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1160421