  We propose a model for the acceleration of charged particles in
interplanetary space that appear during quiet time periods, that is, not
associated with solar activity events like intense flares or coronal mass
ejections. The interaction of charged particles with modeled turbulent
electromagnetic fields, which mimic the fields observed in the interplanetary
medium, is studied. The turbulence is modeled by means of a dynamical
system,the Gledzer-Ohkitani-Yamada (GOY) shell model, which describes the gross
features of the Navier-Stokes equations. The GOY model is used to build a 3-D
velocity field, which in turn is used to numerically solve the ideal
magneto-hydrodynamic (MHD) induction equation, while the electric field is
calculated from the ideal Ohm's law. Particle acceleration in such an
environment is investigated by test particle simulations, and the resulting
energy distributions are discussed and compared to observations of suprathermal
electrons and ions during quiet periods in interplanetary space.

Astrophysics