Coronal Cavities from SDO Observations
Abstract
Coronal cavities are circular darkened regions observed above the solar limb in white light and EUV coronal images. It is a region of low density relative to the surrounding corona. In this study, we are using synoptic maps made from EUV images from the Atmospheric Imager Assembly (AIA) instrument and vector magnetogram images from Helioseismic and Magnetic Imager (HMI) on the SDO to determine the structure and evolution of cavities. The EUV synoptic maps, constructed from circular rings above the limb, are found to best show cavities in 211Å (Fe XIV, 2.0 MK) and 193Å (Fe XII, 1.6 MK) and171Å (Fe IX, 0.6 MK) pass bands. Moreover, 304Å (He II, 0.05 MK) synoptic map best shows the evolution of prominence associated with cavity. Magnetogram synoptic map constructed from the central meridian, shows the underlying magnetic structure of the cavity and prominence. We have also used EUV synoptic map to construct the polar view of the cavities. The high spatial and time resolution combined with the broad temperature coverage provides a consistent picture of the cavity material and the dynamics of the structure.
- Publication:
-
Solar Heliospheric and INterplanetary Environment (SHINE 2013)
- Pub Date:
- June 2013
- Bibcode:
- 2013shin.confE.101K