a1 Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China. e-mail: email@example.com
With the observations from the Solar Dynamics Observatory, we investigate the boundary evolution of a coronal hole (CH). Small-scale solar activity (e.g., coronal jet) can lead to gradual change of CH boundaries (CHBs). Besides gradual change of CHBs, a quiet Sun region can change into a CH region on a large scale when magnetic fields in the photosphere evolve from mixed-polarities into one-polarity dominance. CH regions can also evolve into quiet regions on a large scale when the underlying photosphere becomes mixed-polarity fields from one-polarity dominated fields.
(Online publication June 27 2012)