CME Observations from STEREO

Coronal mass ejections (CMEs) are spectacular ejections of material from the Sun as seen in the coronal field of view. Regular observations are possible with both ground-based and space-based coronagraphs. I present our current understanding of CMEs based on multi-wavelength observations from groundbased instruments as well as from space missions such as SoHO. Based on the continuous and multi-wavelength observations of CMEs from SoHO over a period of more than a solar cycle, the physical properties of CMEs are described. Recent observations of CMEs with the SECCHI coronagraphs, namely COR1 and COR2 aboard the twin STEREO spacecrafts A and B are also presented. STEREO surpasses previous missions by providing a 3-D view of CME structure from two vantage points. Applications of STEREO observations to 3-D reconstructions of the leading edge of CMEs are described.