Don’t forget to register for next week’s webinar featuring Takumi Kera, Tohoku University. He will tell us about his recently completed work on Energy transfer among flow and magnetic fields with different equatorial symmetry during the dipole reversal in a geodynamo simulation using the software package Calypso .
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REMINDER: Register for the webinar THIS THURSDAY FEBRUARY 17th featuring Takumi Kera.
The geomagnetic field has reversed its polarity, and some numerical dynamos have suggested that anti-symmetric flow with respect to the equator plays a role in reversals. Olson et al., (2004) suggested that the equatorial antisymmetric flow is temporarily strengthened, and transports a locally generated reversal magnetic field. Nishikawa and Kusano (2008) explained this asymmetric velocity field enhancement by the increase of energy transfer from magnetic field to asymmetric velocity field in polarity reversal phase by the Lorentz force by simulation with the large magnetic Prandtl number (Pm = 15). In the present research, we investigate how anti-symmetric flow merges and is sustained in the dynamo in which reversals occur with Pm = 5 and Ekman number E = 6e-3.
We perform dynamo simulations using Calypso (Matsui et al., 2014) to represent dipole dominant dynamo with reversals. We investigate the buoyancy flux and work of the Lorentz force in terms of the equatorial symmetry in the stable polarity phase and in the polarity reversal phase, respectively.