9–13 Mar 2015
Albanova, Stockholm
Europe/Stockholm timezone

On the penumbra - Evershed flow - moat connection: A modeling perspective

13 Mar 2015, 09:00
40m
Oskar Klein Auditorium (Albanova, Stockholm)

Oskar Klein Auditorium

Albanova, Stockholm

Speaker

Matthias Rempel (HAO/NCAR)

Description

We present a series of high-resolution sunspot simulations that cover a time span of up to 100 hours. The simulation domain covers the upper 18 Mm of the convection zone and we use open boundaries that do not maintain the initial field structure against decay driven by convective motions. We consider two setups: A sunspot simulation with penumbra, a "naked-spot" simulation in which we removed the penumbra after 20 hours through a change in the magnetic top boundary condition. Both spots are surrounded by a moat flow of a few 100 m/s flow speed in the photosphere extending to about twice the spot radius and several Mm in depth. The flow system is more extended for the spot with penumbra. In addition we find in proximity of both spots a region with significantly reduced convective flow velocities and downflow filling factor. Both effects stabilize the spots against decay, in the case of the spot with penumbra this leads to an almost stationary solution over the time span simulated.

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