Toroidal Plasma Thruster for Deep Space Flights

Abstract

A conceptual, theoretical assessment of using the toroidal fusion reactor, tokamak, for deep space interplanetary and interstellar missions is presented. Toroidal thermonuclear fusion reactors, such as tokamaks and stellarators, are unique for space propulsion, allowing a design with the magnetic configuration localized inside the toroidal magnetic field coils. Plasma energetic ions, including charged fusion products, can escape such closed configuration at certain conditions as a result of vertical drift in the toroidal rippled magnetic field. Escaping particles can be used for direct propulsion (because toroidal drift is directed one way vertically) or to create and heat externally confined plasma, so that the latter can be used for propulsion. In contrast to other fusion concepts proposed for space propulsion, this concept utilizes the natural drift motion of charged particles out of the closed magnetic field configuration. Also, using deuterium-tritium (D-T) plasma is a novel way to use fusion neutrons with the energy of 14 MeV for direct propulsion (neutron rocket) for out of solar system missions. A special design of the blanket of the reactor allows neutrons to escape the device in a preferable direction. This provides a direct (partial) conversion of fusion energy into thrust.