Scaling Model for SPT and TAL Thrusters

Scaling methods are a straightforward way to design new thrusters at different power levels. Based on the general equations, this work derives the scaling rules from those equations and presents a model for thruster with anode layer (TAL) and stationary plasma thrusters (SPTs) that encompass the scaling methods described until now. With the exception of the magnetic field, the scaling rules derived can be used for both TAL and SPT. In addition, this model is used to study the impact of the different scaling methods in the performance of the thruster. In particular, how the total thruster efficiency is affected through the current efficiency and the influence of this efficiency loss in the thrust. Accordingly, using the rules derived from the general equations for the magnetic field, the possible conflicts with the electron confinement given by the Larmor Radius for both SPT and TAL thrusters are studied. Finally, it is shown how the selected scaling method strongly affects the expected lifetime of the thruster. In this aspect, the strict scaling results to be the most rigorous method, whereas the length extension method allows for further improvement of the lifetime.