MHD Analysis of Flow Fields Around Magneto Plasma Sail

Abstract

Magneto Plasma Sail (Mini-magnetospheric plasma propulsion = M2P2) is one of propulsion systems which captures the momentum of the solar wind by a large artificial magnetosphere around a spacecraft. Magneto Plasma Sail injects plasma into the small magnetosphere and inflates the small magnetosphere to the large magentosphere. This technique is called “magnetic field inflation”. Performace of Magneto Plasma Sail depends on the efficiency of magnetic field inflation and the efficiency of momentum transfer from solar wind to spacecraft. In this research, the efficiencies of Magneto Plasma Sail were verified using numerical simulation and theoretical analysis based on magnetohydrodynamics, and the performance was discussed by estimating the ratio of thrust to force from injected plasma. As results, the efficiency of magnetic field inflation was estimated as the structure of inflated magnetic field and the dipole magnetic field proportional to the distance to minus 3rd power is inflated to the magnetic field proportional to the distance to minus 1st power. The effciency of momentum transfer from solar wind to spacecraft was estimated as a drag coefficient and the drag coefficient is 0.28. The ratio of thrust to force from injected plasma was calculated to be 0.7 in this research, therefore magnetic field inflation has to be conducted by plasma jet in lower energy to achive high efficiency of Magneto Plasma Sail.