Numerical study of beam extraction phenomena in an ion thruster

Ion beam extraction phenomenon is one of the most important processes in an ion propulsion system because ion beam current and beam accelerating volta ge dominate thrust. In order to evaluate the beam extraction capability, wh ich is determined by the interrelation between discharge plasma properties and beam accelerating conditions, there is a need to understand the problem s of ion sheath formation. This study has been performed to develop a numer ical simulation code which is capable of investigating the ion beam extract ion phenomena in the ion thruster. In the calculation, both ions and electr ons were treated as particles in a particle-in-cell routine to determine th e ion sheath self-consistently. The calculation results of electric potenti al contours and extracted currents were compared with the experimental ones and they were found to be in good agreement. In addition, it was confirmed that the ion beam extraction capability can be simulated in a wide range o f beam accelerating voltage.