Assessment of a Numerical Approach Suitable for the M2P2 Problem

ABSTRACT

The magnetic sail is a quite new concept of space propulsion utilising the solar wind in order to transfer momentum to a magnetic field source. The magnetic field size can be increased significantly by injecting a plasma into the center of the magnetic bubble. This concept is called Mini-Magnetospheric Plasma Propulsion (M2P2) system. The plasma injection shall create a magnetosphere with a diameter of several km. Because of these large scales, experiments are difficult and most of the published studies on this concept are therefore based on numerical investigations. The applied approaches, MHD and hybrid (MHD/kinetic), are analysed in the context of the strongly diverging results in the published studies on e.g. magnetic field decay. A validity parameter (Damköhler number) for the simulation methodologies is proposed and also an analytical estimation of basic M2P2 characteristics is presented. Finally, a recommendation is given for future M2P2 simulation methodologies which, for the sake of accuracy, should base on purely kinetic approaches.