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.
We describe observations of a white-light flare (SOL2011-02-24T07:35:00, M3.5) close to the limb of the Sun, from which we obtain estimates of the heights of the optical continuum sources and those of the associated hard X-ray sources.For this purpos
e we use hard X-ray images from the Reuven Ramaty High Energy Spectroscopic Imager (RHESSI), and optical images at 6173 AA from the Solar Dynamics Observatory (SDO). We find that the centroids of the impulsive-phase emissions in white light and hard X-rays (30-80 keV) match closely in central distance (angular displacement from Sun center), within uncertainties of order 0.2. This directly implies a common source height for these radiations, strengthening the connection between visible flare continuum formation and the accelerated electrons. We also estimate the absolute heights of these emissions, as vertical distances from Sun center. Such a direct estimation has not been done previously, to our knowledge. Using a simultaneous 195 AA image from the Solar-Terrestrial RElations Observatory (STEREO-B) spacecraft to identify the heliographic coordinates of the flare footpoints, we determine mean heights above the photosphere (as normally defined; tau = 1 at 5000 AA) of 305 pm 170 km and 195 pm 70 km, respectively, for the centroids of the hard X-ray (HXR) and white light (WL) footpoint sources of the flare. These heights are unexpectedly low in the atmosphere, and are consistent with the expected locations of tau = 1 for the 6173 AA and the ~40 keV photons observed, respectively.
We present observational results of a type II burst associated with a CME-CME interaction observed in the radio and white-light wavelength range. We applied radio direction-finding techniques to observations from the STEREO and Wind spacecraft, the r
esults of which were interpreted using white-light coronagraphic measurements for context. The results of the multiple radio-direction finding techniques applied were found to be consistent both with each other and with those derived from the white-light observations of coronal mass ejections (CMEs). The results suggest that the Type II burst radio emission is causally related to the CMEs interaction.
