Abstract
Protons, heavy nuclei and electrons are seen to be emitted from solar flares with energies extending up to the relativistic region. Three different aspects of these observations will be discussed: (1) Transport processes along magnetic flux tubes in interplanetary space which distort the source spectra and, due to corotation effects, bring different solar source longitudes into view. (2) Solar longitudinal dependence of the intensity profiles which yields information on energetic particle motion in the corona and the large scale coronal magnetic structure. (3) Charge composition measurements which show various enhancements of heavy nuclei fluxes relative to normal coronal abundances and thus yield information on the composition and state of ionization of the acceleration region.