Top to third panels: Sequential magnetograms showing the emergence and formation of AR 11130 obtained by SDO/HMI. Bottom panel: Time evolution of the power spectrum produced from the sequential magnetograms. Color varies with time from purple (2012-Nov-27 00:00 UT) to red (2012-Dec-02 00:00 UT). Adapted from Toriumi, Hayashi, and Yokoyama (2014) by permission of the AAS. (Color online)