We report observations of white-light ejecta in the low corona , for two X-class flares on the 2013 May 13 , using data from the Helioseismic and Magnetic Imager ( HMI ) of the Solar Dynamics Observatory .
At least two distinct kinds of sources appeared ( chromospheric and coronal ) , in the early and later phases of flare development , in addition to the white-light footpoint sources commonly observed in the lower atmosphere .
The gradual emissions have a clear identification with the classical loop-prominence system , but are brighter than expected and possibly seen here in the continuum rather than line emission .
We find the HMI flux exceeds the radio/X-ray interpolation of the bremsstrahlung produced in the flare soft X-ray sources by at least one order of magnitude .
This implies the participation of cooler sources that can produce free-bound continua and possibly line emission detectable by HMI .
One of the early sources dynamically resembles “ coronal rain ” , appearing at a maximum apparent height and moving toward the photosphere at an apparent constant projected speed of 134 \pm 8 \mathrm { km~ { } s ^ { -1 } } .
Not much literature exists on the detection of optical continuum sources above the limb of the Sun by non-coronagraphic instruments , and these observations have potential implications for our basic understanding of flare development , since visible observations can in principle provide high spatial and temporal resolution .