Particle acceleration in solar flares and coronal mass ejections

The Sun accelerates ions up to tens of GeV and electrons up to 100s of MeV in solar flares and coronal mass ejections. The energy in the accelerated tens-of-keV electrons and possibly similar to1 MeV ions constitutes a significant fraction of the total energy released in a flare, implying that the particle acceleration and flare energy release mechanisms are intimately related. The total rate of energy release in transients from flares down to microflares/nanoflares may be significant for heating the active solar corona. Shock waves driven by fast CMEs appear to accelerate the high-energy particles in large solar energetic particle events detected at 1 AU. Smaller SEP events are dominated by similar to1 to tens-of-keV electrons, with low fluxes of up to a few MeV/nucleon ions, typically enriched in He-3. The acceleration in gamma-ray flares appears to resemble that in these small electron-He-3 SEP events.