LARGE-SCALE BRIGHTENINGS ASSOCIATED WITH FLARES

Flare-associated large-scale (> 10(10) cm) X-ray brightenings, the so-called 'giant arches' in the nomenclature of Svestka and co-workers, were discovered in images obtained by the SMM Hard X-ray Imaging Spectrometer hours after the onset of two-ribbon flares. The apparent correlation between both phenomena suggested that they could be interpreted in the framework of the same model. In this paper we show that large-scale loop brightenings, of sizes similar to the giant arches. occur also in association with confined flares in complex active regions. In these cases, the relation between the large-scale structure and the underlying flare is clearly given by the magnetic field topology. We also show that energization of these structures can be partially due to the injection of suprathermal particles that are accelerated at the separator region. We discuss the implications of these results within the framework of the interacting loops picture of flares and of the giant arch phenomenology.