Tracking Outward Propagating Small-Scale Structures from EUVI through COR1 and COR2

The challenge of connecting slow solar wind variability to its source at the Sun is primarily due to the limitations on observational data of the low corona. Instrumental light scattering is higher in coronagraph observations very close to the solar surface, resulting in poor signal-to-noise ratios. Additionally, the non-radial nature of the coronal structures in this region hampers the tracking of small-scale structures in observations, since they produce weaker signals. Our work focuses on developing and applying advanced image processing techniques to solar imaging data in an effort to connect the low corona to the high corona with a focus on the identification of the sources of small-scale structures in the slow solar wind. The inner coronagraph, COR1, onboard the STEREO spacecraft, observes the low corona from ~1.1 to 4 R_s, imaging the important connection between the solar wind, its source, and the formation of the solar wind structures. We have developed an approach for processing COR1 that allows the tracking of small-scale structures. The core process is a bandpass filter of the data over time, where the signal from high frequency noise is suppressed, as well as slowly evolving structures. We applied this method to a 10-day period of observations during solar minimum and compared them to observations from the imager EUVI and outer coronagraph COR2. Height-time profiles reveal structures propagating through the different fields of view, establishing a connection between the low and high corona. Further analysis will allow us to characterize these structures and determine occurrence frequencies, size scales, formation height and mechanism. Our method for processing COR1 opens the door to ~13 years of STEREO/COR1 data for studies in general of the connection between the low and high corona, and specifically of small-scale coronal structures.