In-FEEP ion beam profiles were obtained for a variety of thrust values ranging from 0.49 up to 115.5 μN. The beam shape was found to be close to a cosine in low thrust levels and resembled a Gaussian distribution at high thrust levels. Data processing of the obtained profiles to evaluate the thrust correction factor which is in close agreement to direct thrust measurements. Thrust vector angle and beam divergence were within the expected ranges.

A multi-emitter configuration was tested and the ion beam profiles showed no ion beam interaction. Numerical simulations based on a 3D Particle-In-Cell (PIC) code, successfully tested against experimental measurements, verified this result even for a vacuum environment with no ambient electrons that can provide neutralization.