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Session 2 - The Solar Photosphere and Magnetic Field.
Display session, Monday, June 10
We developed an algorithm to outline the chromospheric network on a 2-day sequence of Ca II K observations made from the South Pole, in order to study the sizes of supergranulation cells. We find an average cell diameter that is substantially smaller than the generally quoted value of 30--35 Mm, as first determined by Simon and Leighton (1964) from autocorrelation curves of the line--of--sight velocities. We argue that the autocorrelation method is preferentially weighted towards large cells, which results in an estimated size that is approximately 1.5 to 2 times larger than the true average cell diameter. A comparable difference should occur in studies of the size scale of the chromospheric network. In addition, we find that secondary maxima to the autocorrelation peaks of the Doppler signal imply that the correlation between cell size and flow velocity is weak at best. If such a correlation should exist, it would be too weak to affect the spacing of the secondary maxima of the autocorrelation function.
Program listing for Monday