In this work, we present observations of energetic particles injected by solar flares into extended solar magnetic looplike structures. From the developement of the angular distributions of the intensities of energetic protons (Ep ?300 keV, Ep ?25 MeV) and electrons (Ec ?220 keV), we have inferred that energetic particles are bouncing between two magnetic mirrors and have obtained for the first time estimates of the extent of magnetic loops to distances ~3.5 AU form the sun.