The Workings of an Electrical Engine

In an electric engine, the energy needed to accelerate the particles of the propellant is provided by an on-board electric power supply that is connected to both the ionization chamber and to the neutralizer at the nozzle of the rocket.

The ionization chamber to which the power supply is connected is the site of particle acceleration. Propellant is pumped into the ionization chamber where it is passed between two grids that ionize it. The electrical field between the grids provides the positive ions of the propellant with an acceleration up to the velocity, v. Once ionized, the neutralizer, which is also connected to the power supply, fires electrons at the accelerated fuel particles. The purpose of these electrons is to counteract the positive charge of the particles, and to assure that the exhaust of the rocket is electrically neutral. The strength of the beam of electrons being fired at the exhaust depends on the amount of fuel being ionized and the thrust achieved. The relationship of the mentioned variables with the rate of fuel consumption is given by the equation:

In this equation,

F= thrust force
m= propellant consumption
v= exhaust velocity
W= beam power

The application of the previous equation with the rocket equation explains the behavior of all electrically propelled rockets.