A ‘solar flare’ resulting from a sudden release of the magnetic energy stored in the solar corona is the largest exploding phenomenon in our solar system. Once a flare occurs, a large amount of coronal plasma is strongly heated and ejected toward the interplanetary space. In a huge flare, very high-energy particles are also produced. However, the mechanism of particle acceleration is not understood yet. When the plasma ejected through the process of solar flares reaches our geospace, as it sometimes does, it has the potential to strongly disturb the Earth’s magnetosphere, yielding geomagnetic storms and aurora. Energetic particles may cause damage to satellites, and astronauts may also be exposed to them. Particle acceleration in solar flares is a very important issue to understand, not only from a scientific but also from a space-environmental point of view,
In phase I of the GEMSIS project (2007 - 2009), the main goal of GEMSIS-Sun was to understand particle acceleration mechanisms in solar flares, through development of a numerical model of energetic particles and data analysis of space- and ground-based observations.