Hard X-ray and metric/decimetric spatially resolved observations of occulted solar flares
Résumé
The main goal of the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) mission is to investigate particle acceleration and energy release in solar flares, through imaging and spectroscopy of hard X-ray(HXR)/ gamma-ray continuum and gamma-ray lines emitted by energetic electrons and ions interacting with the solar atmosphere. RHESSI has observed several flares associated with active regions behind the limb, thus imaging coronal non-thermal HXR components up to several tens of keV. Complementary observations of HXR emitting electrons are provided by the radio emission of non-thermal electrons produced in a wide range of coronal heights in the centimetric to metric frequency range. Some of the occulted flares observed by RHESSI (on 16/04/02 and 04/08/02) were also observed at metric/decimetric wavelengths by the Nançay Radioheliograph (NRH) which provided images of the radio emission produced in the solar corona at five frequencies in the 150-450 MHz range. We shall present here some comparisons of the time evolutions of the X-ray images observed in different energy bands by RHESSI and of the time evolutions of the radio emission sites at the five frequencies observed by the NRH to investigate the possible link between the coronal hard X-ray emissions and the production of non-thermal radio emitting electrons.