Two-Dimensional Particle-In-Cell Simulation of Magnetic Sails

Abstract

A magnetic sail is spacecraft propulsion that produces an artificial magnetosphere to block solar wind particles and thus impart momentum to accelerate a spacecraft. In the present study, the authors conducted two-dimensional particle-in-cell simulations on small-scale magnetospheres to investigate thrust characteristics of a magnetic sail and its derivative, magnetoplasma sail, in which the magnetosphere is inflated by an additional plasma injection. As a result, the authors found that the electron Larmor motion and the charge separation become significant on such a small-scale magnetosphere and the thrust of the magnetic sail is affected by the cross-sectional size of the charge-separated magnetosphere. The authors also reveal that the plasma injection, on the condition that the kinetic energy of plasma is smaller than the local magnetic field energy (), can significantly inflate the magnetosphere by inducing diamagnetic current in the same direction as the onboard coil current. As a result, the magnetoplasma sail thrust is increased effectively by an additional plasma injection: the magnetoplasma sail thrust () becomes up to 7.5 times larger than the original thrust of the magnetic sail (). In addition, they found that the thrust gain of the magnetoplasma sail, defined as “magnetoplasma sail thrust/(magnetic sail injection thrust)” becomes up to 2.2.