SIMULATION STUDIES OF ACCELERATION OF HEAVY-IONS AND THEIR ELEMENTAL COMPOSITIONS

By using a one-dimension (one spatial coordinate and three-velocity co mponents), electromagnetic particle simulation code with full ion and electron dynamics, we have studied the acceleration of heavy ions by a nonlinear magnetosonic wave in a multi-ion-species plasma. First, we describe the mechanism of heavy ion acceleration by magnetosonic waves . We then investigate this by particle simulations. The simulation pla sma contains four ion species: H, He, O, and Fe. The number density of He is taken to be 10% of that of H, and those of O and Fe are much lo wer. Simulations confirm that, as in a single-ion-species plasma, some of the hydrogen can be accelerated by the longitudinal electric field formed in the wave. Furthermore, they show that magnetosonic waves ca n accelerate all the particles of all the heavy species (He, O, and Fe ) by a different mechanism, i.e., by the transverse electric field. Th e maximum speeds of the heavy species are about the same, of the order of the wave propagation speed. These are in good agreement with theor etical prediction. These results indicate that, if high-energy ions ar e produced in the solar corona through these mechanisms, the elemental compositions of these heavy ions can be similar to that of the backgr ound plasma, i.e., the corona.