The Heliosphere as an Astrophysical Laboratory for Particle Acceleration

Abstract
Particle acceleration is one of the most important topics in plasma astrophysics as well as in cosmic-ray astrophysics. The heliosphere is an ideal astrophysical laboratory, wherein one can observe in situ the elementary mechanisms involved in the particle acceleration processes. Two phenomena of special interest are stochastic acceleration in the magnetohydrodynamic turbulence around comets and stochastic shock acceleration at interplanetary shock waves.