Astronomy and Astrophysics – Astronomy
Scientific paper
Jan 2007
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007geoji.168...27a&link_type=abstract
Geophysical Journal International, Volume 168, Issue 1, pp. 27-39.
Astronomy and Astrophysics
Astronomy
14
Core Flow, Dynamo Theory, Geomagnetic Secular Variation, Magnetic Diffusion
Scientific paper
We test the quality of a new core flow imaging method that incorporates constraints on flow helicity, using synthetic magnetic secular variation data from 3-D self-consistent numerical dynamo models. Comparison with the dynamo model flows reveals that our imaging method delineates most of the main large-scale flow features, both in pattern and magnitude. The dynamo model flows are characterized by high-latitude vortices, some equatorial symmetry, columnar convection and a significant amount of flow along radial magnetic field contours. Our inversion method correctly images these aspects of the flows. The correlation coefficient between the dynamo velocity and the imaged velocity exceeds 0.5 in cases with large-scale flow and magnetic field pattern, but degrades substantially in more complex cases when the scale of the secular variation is small. The magnitude of the imaged velocity depends on the a priori-assumed ratio of tangential divergence to radial vorticity k, in some resemblance to the damping parameter in spectral methods, although with our method the misfit is insensitive to k-values. Including tangential magnetic diffusion in core flow inversion improves the quality of the imaged velocity pattern. The largest artefacts in the imaged velocities are due to unmodelled radial magnetic diffusion and truncation of the input magnetic field.
Amit Hagay
Christensen Ulrich
Olson Peter
No associations
LandOfFree
Tests of core flow imaging methods with numerical dynamos 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 Tests of core flow imaging methods with numerical dynamos, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Tests of core flow imaging methods with numerical dynamos will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1254612