Influence of instabilities on plasma flow around a comet

The ion pickup process is examined in a multifluid hydrodynamic approximation which allows for relative motion, along the magnetic field, of the newly created ions and the original fluid. If this relative motion is appreciable, the cometary ion flow will not be exactly antisunward, and its reaction on the solar wind will deflect the solar wind in the opposite direction. Fluid equations are given, but they would necessitate calculating the flow of several fluid species.