Three-dimensional hybrid simulation of magnetized plasma flow around an obstacle

The interaction between the magnetized plasma flow and an obstacle was investigated in the computer simulations described here by using a three-dimensional hybrid code (kinetic ions and massless fluid electrons). The results, which are relevant to the interaction between the solar wind and an unmagnetized planet (Venus or Mars), show that fundamental structures (bow shock and magnetotail) are formed. When a reflecting boundary is used at the obstacle, the magnetic field configuration was clearly asymmetrical in the direction of the convection electric field. This asymmetry is a result of differences in ion acceleration due to the convection electric field. Asymmetry is also evident when the size of the obstacle is close to the Larmor radius of protons. The shock of a smaller obstacle is weaker than that of a larger obstacle, but the shock size is almost independent of the obstacle size.