Speaker
Aaron Birch
(Max Planck Institute for Solar System Research)
Description
We have carried out a study of about one hundred emerging
sunspot regions observed by the HMI instrument. For each
active region, we measure flows by applying helioseismic
holography to time series of Doppler images and also by
applying local correlation tracking to intensity images. We
show that these two methods give very similar results in
non-magnetic regions. We find that the active regions in our
survey tend to emerge in regions where the horizontal flows
are converging. Comparison of the observed flows with
results from MURaM simulations of flux emergence show that
the initial rise speed of magnetic flux concentrations at
depths of about 20 Mm cannot be substantially larger than
the convective flow speeds.
Primary author
Aaron Birch
(Max Planck Institute for Solar System Research)
