Dynamics of pick-up ions in collisionless velocity shears

摘要: We study the motion of charged particles in large-scale velocity shears that are produced interaction magnetized plasma winds and obstacles. The purpose analysis is to account for observation strongly energetic contaminant ions region solar wind with plane-tary/cometary non-magnetic ionospheric obstacles (Venus, Mars, comets). convective electric field set up by streaming incorporated equation born a shear. Neglecting collisions back reaction on wind, trajectories computed as function shear properties well mass magnetic configuration. For linear dependence across shear, problem solved analytically we find particle can have either purely oscillatory behavior or grow exponentially time depending value dimensionless parameter proportional product gradient cyclotron frequency ion trajectories. In latter case strong acceleration be achieved. Adopting flow appropriate cometary planetary environments, explore potential importance mechanism discussed explain presence superthermal filamentary structures such regions.